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Sample records for act coding scheme

  1. Optimal probabilistic dense coding schemes

    Science.gov (United States)

    Kögler, Roger A.; Neves, Leonardo

    2017-04-01

    Dense coding with non-maximally entangled states has been investigated in many different scenarios. We revisit this problem for protocols adopting the standard encoding scheme. In this case, the set of possible classical messages cannot be perfectly distinguished due to the non-orthogonality of the quantum states carrying them. So far, the decoding process has been approached in two ways: (i) The message is always inferred, but with an associated (minimum) error; (ii) the message is inferred without error, but only sometimes; in case of failure, nothing else is done. Here, we generalize on these approaches and propose novel optimal probabilistic decoding schemes. The first uses quantum-state separation to increase the distinguishability of the messages with an optimal success probability. This scheme is shown to include (i) and (ii) as special cases and continuously interpolate between them, which enables the decoder to trade-off between the level of confidence desired to identify the received messages and the success probability for doing so. The second scheme, called multistage decoding, applies only for qudits ( d-level quantum systems with d>2) and consists of further attempts in the state identification process in case of failure in the first one. We show that this scheme is advantageous over (ii) as it increases the mutual information between the sender and receiver.

  2. Modified Mean-Pyramid Coding Scheme

    Science.gov (United States)

    Cheung, Kar-Ming; Romer, Richard

    1996-01-01

    Modified mean-pyramid coding scheme requires transmission of slightly fewer data. Data-expansion factor reduced from 1/3 to 1/12. Schemes for progressive transmission of image data transmitted in sequence of frames in such way coarse version of image reconstructed after receipt of first frame and increasingly refined version of image reconstructed after receipt of each subsequent frame.

  3. Modified Mean-Pyramid Coding Scheme

    Science.gov (United States)

    Cheung, Kar-Ming; Romer, Richard

    1996-01-01

    Modified mean-pyramid coding scheme requires transmission of slightly fewer data. Data-expansion factor reduced from 1/3 to 1/12. Schemes for progressive transmission of image data transmitted in sequence of frames in such way coarse version of image reconstructed after receipt of first frame and increasingly refined version of image reconstructed after receipt of each subsequent frame.

  4. Practical Coding Schemes for Cognitive Overlay Radios

    CERN Document Server

    Kurniawan, Ernest; Rini, Stefano

    2012-01-01

    We develop practical coding schemes for the cognitive overlay radios as modeled by the cognitive interference channel, a variation of the classical two user interference channel where one of the transmitters has knowledge of both messages. Inspired by information theoretical results, we develop a coding strategy for each of the three parameter regimes where capacity is known. A key feature of the capacity achieving schemes in these regimes is the joint decoding of both users' codewords, which we accomplish by performing a posteriori probability calculation over a combined trellis. The schemes are shown to perform close to the capacity limit with low error rate.

  5. Problems of robustness for universal coding schemes

    OpenAIRE

    V'yugin, V. V.

    2008-01-01

    The Lempel-Ziv universal coding scheme is asymptotically optimal for the class of all stationary ergodic sources. A problem of robustness of this property under small violations of ergodicity is studied. A notion of deficiency of algorithmic randomness is used as a measure of disagreement between data sequence and probability measure. We prove that universal compressing schemes from a large class are non-robust in the following sense: if the randomness deficiency grows arbitrarily slowly on i...

  6. Vector lifting schemes for stereo image coding.

    Science.gov (United States)

    Kaaniche, Mounir; Benazza-Benyahia, Amel; Pesquet-Popescu, Béatrice; Pesquet, Jean-Christophe

    2009-11-01

    Many research efforts have been devoted to the improvement of stereo image coding techniques for storage or transmission. In this paper, we are mainly interested in lossy-to-lossless coding schemes for stereo images allowing progressive reconstruction. The most commonly used approaches for stereo compression are based on disparity compensation techniques. The basic principle involved in this technique first consists of estimating the disparity map. Then, one image is considered as a reference and the other is predicted in order to generate a residual image. In this paper, we propose a novel approach, based on vector lifting schemes (VLS), which offers the advantage of generating two compact multiresolution representations of the left and the right views. We present two versions of this new scheme. A theoretical analysis of the performance of the considered VLS is also conducted. Experimental results indicate a significant improvement using the proposed structures compared with conventional methods.

  7. Password Authentication Based on Fractal Coding Scheme

    Directory of Open Access Journals (Sweden)

    Nadia M. G. Al-Saidi

    2012-01-01

    Full Text Available Password authentication is a mechanism used to authenticate user identity over insecure communication channel. In this paper, a new method to improve the security of password authentication is proposed. It is based on the compression capability of the fractal image coding to provide an authorized user a secure access to registration and login process. In the proposed scheme, a hashed password string is generated and encrypted to be captured together with the user identity using text to image mechanisms. The advantage of fractal image coding is to be used to securely send the compressed image data through a nonsecured communication channel to the server. The verification of client information with the database system is achieved in the server to authenticate the legal user. The encrypted hashed password in the decoded fractal image is recognized using optical character recognition. The authentication process is performed after a successful verification of the client identity by comparing the decrypted hashed password with those which was stored in the database system. The system is analyzed and discussed from the attacker’s viewpoint. A security comparison is performed to show that the proposed scheme provides an essential security requirement, while their efficiency makes it easier to be applied alone or in hybrid with other security methods. Computer simulation and statistical analysis are presented.

  8. Systematic Luby Transform codes as incremental redundancy scheme

    CSIR Research Space (South Africa)

    Grobler, TL

    2011-09-01

    Full Text Available Systematic Luby Transform (fountain) codes are investigated as a possible incremental redundancy scheme for EDGE. The convolutional incremental redundancy scheme currently used by EDGE is replaced by the fountain approach. The results...

  9. Optimal coding schemes for conflict-free channel access

    Science.gov (United States)

    Browning, Douglas W.; Thomas, John B.

    1989-10-01

    A method is proposed for conflict-free access of a broadcast channel. The method uses a variable-length coding scheme to determine which user gains access to the channel. For an idle channel, an equation for optimal expected overhead is derived and a coding scheme that produces optimal codes is presented. Algorithms for generating optimal codes for access on a busy channel are discussed. Suboptimal schemes are found that perform in a nearly optimal fashion. The method is shown to be superior in performance to previously developed conflict-free channel access schemes.

  10. Properties of Codes in the Johnson Scheme

    CERN Document Server

    Silberstein, Natalia

    2010-01-01

    Codes which attain the sphere packing bound are called perfect codes. The most important metrics in coding theory on which perfect codes are defined are the Hamming metric and the Johnson metric. While for the Hamming metric all perfect codes over finite fields are known, in the Johnson metric it was conjectured by Delsarte in 1970's that there are no nontrivial perfect codes. The general nonexistence proof still remains the open problem. In this work we examine constant weight codes as well as doubly constant weight codes, and reduce the range of parameters in which perfect codes may exist in both cases. We start with the constant weight codes. We introduce an improvement of Roos' bound for one-perfect codes, and present some new divisibility conditions, which are based on the connection between perfect codes in Johnson graph J(n,w) and block designs. Next, we consider binomial moments for perfect codes. We show which parameters can be excluded for one-perfect codes. We examine two-perfect codes in J(2w,w) a...

  11. MULTIPLE TRELLIS CODED ORTHOGONAL TRANSMIT SCHEME FOR MULTIPLE ANTENNA SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, a novel multiple trellis coded orthogonal transmit scheme is proposed to exploit transmit diversity in fading channels. In this scheme, a unique vector from a set of orthogonal vectors is assigned to each transmit antenna. Each of the output symbols from the multiple trellis encoder is multiplied with one of these orthogonal vectors and transmitted from corresponding transmit antennas. By correlating with corresponding orthogonal vectors, the receiver separates symbols transmitted from different transmit antennas.This scheme can be adopted in coherent/differential systems with any number of transmit antennas. It is shown that the proposed scheme encompasses the conventional trellis coded unitary space-time modulation based on the optimal cyclic group codes as a special case. We also propose two better designs over the conventional trellis coded unitary space-time modulation. The first design uses 8 Phase Shift Keying (8-PSK) constellations instead of 16 Phase Shift Keying (16-PSK) constellations in the conventional trellis coded unitary space-time modulation. As a result, the product distance of this new design is much larger than that of the conventional trellis coded unitary space-time modulation. The second design introduces constellations with multiple levels of amplitudes into the design of the multiple trellis coded orthogonal transmit scheme. For both designs, simulations show that multiple trellis coded orthogonal transmit schemes can achieve better performance than the conventional trellis coded unitary space-time schemes.

  12. Evaluation of three coding schemes designed for improved data communication

    Science.gov (United States)

    Snelsire, R. W.

    1974-01-01

    Three coding schemes designed for improved data communication are evaluated. Four block codes are evaluated relative to a quality function, which is a function of both the amount of data rejected and the error rate. The Viterbi maximum likelihood decoding algorithm as a decoding procedure is reviewed. This evaluation is obtained by simulating the system on a digital computer. Short constraint length rate 1/2 quick-look codes are studied, and their performance is compared to general nonsystematic codes.

  13. Rate-embedded differential space-time-frequency coding scheme

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In multiple-input-multiple-output orthogonal-frequency-division-multiplexing (MIMO-OFDM) system, a rate-embedded differential space-time-frequency (DSTF) coding scheme was proposed. Both the conventional space-time codes and coding techniques in frequency domain were employed to build high rate and low rate space-time-frequency message matrices. Then both types of message matrices were differentially transmitted alternately in the frequency domain. Consequently, the total transmission rate could be improved greatly. At receiver, a simple decision feedback differential detector (SDF-DD) was adopted to further enhance the total error performance with approximate DD complexity. Simulation results verified that the proposed scheme can implement high rate and high reliability differential transmission. Compared with the conventional DSTF coding schemes, the proposed scheme achieves higher spectral efficiency and much better error performance.

  14. Video coding scheme using DCT-pyramid vector quantization.

    Science.gov (United States)

    Dalessandro, P; Lancini, R

    1995-01-01

    A new and effective video coding scheme for contribution quality is proposed. The CMTT/2, a joint committee of CCIR and CCITT, has proposed a video coding scheme (already approved at European level by ETS) working at 34-45 Mbit/s. Basically this proposal includes a DCT transform for spatial correlation removal and motion compensation for temporal correlation removal. The individual transform coefficients are then scalar quantized with a non uniform bit assignment. Starting from the CMTT/2 proposal, the study presents a new video coding scheme designed using a vector quantizer solution instead of the scalar one. Specifically, the pyramid vector quantization (PVQ) has been chosen as the vector quantization method as it is able to reduce the DCT coefficients Laplacian distribution. Simulation results show that the proposed video coding scheme gives the same contribution quality at 22 Mbit/s as the one obtained with the CMTT/2 proposal at 45 Mbit/s.

  15. Optical Packet Switching Scheme Using Multi-optical-code Labels

    Institute of Scientific and Technical Information of China (English)

    LI Shu-wen; ZHANG Qi; YU Chong-xiu; XIN Xiang-jun; XIONG Fei

    2009-01-01

    Proposed is a novel optical code(OC) label switching scheme in which an optical label is constructed by multiple parallel optical codes. The performances of splitting loss and BER are simulated and analyzed. Simulation results show that the proposed label can be correctly recognized to perform packet switching. Compared with reported schemes using one OC as a label, the splitting loss in our proposal is lowered.

  16. A novel chaotic encryption scheme based on arithmetic coding

    Energy Technology Data Exchange (ETDEWEB)

    Mi Bo [Department of Computer Science and Engineering, Chongqing University, Chongqing 400044 (China)], E-mail: mi_bo@163.com; Liao Xiaofeng; Chen Yong [Department of Computer Science and Engineering, Chongqing University, Chongqing 400044 (China)

    2008-12-15

    In this paper, under the combination of arithmetic coding and logistic map, a novel chaotic encryption scheme is presented. The plaintexts are encrypted and compressed by using an arithmetic coder whose mapping intervals are changed irregularly according to a keystream derived from chaotic map and plaintext. Performance and security of the scheme are also studied experimentally and theoretically in detail.

  17. An Extended Network Coding Opportunity Discovery Scheme in Wireless Networks

    CERN Document Server

    Zhao, Yunlong; Iwai, Masayuki; Sezaki, Kaoru; Tobe, Yoshito; 10.5121/ijcnc.2012.4106

    2012-01-01

    Network coding is known as a promising approach to improve wireless network performance. How to discover the coding opportunity in relay nodes is really important for it. There are more coding chances, there are more times it can improve network throughput by network coding operation. In this paper, an extended network coding opportunity discovery scheme (ExCODE) is proposed, which is realized by appending the current node ID and all its 1-hop neighbors' IDs to the packet. ExCODE enables the next hop relay node to know which nodes else have already overheard the packet, so it can discover the potential coding opportunities as much as possible. ExCODE expands the region of discovering coding chance to n-hops, and have more opportunities to execute network coding operation in each relay node. At last, we implement ExCODE over the AODV protocol, and efficiency of the proposed mechanism is demonstrated with NS2 simulations, compared to the existing coding opportunity discovery scheme.

  18. A Novel Block-Based Scheme for Arithmetic Coding

    Directory of Open Access Journals (Sweden)

    Qi-Bin Hou

    2014-06-01

    Full Text Available It is well-known that for a given sequence, its optimal codeword length is fixed. Many coding schemes have been proposed to make the codeword length as close to the optimal value as possible. In this paper, a new block-based coding scheme operating on the subsequences of a source sequence is proposed. It is proved that the optimal codeword lengths of the subsequences are not larger than that of the given sequence. Experimental results using arithmetic coding will be presented.

  19. Wavelet based hierarchical coding scheme for radar image compression

    Science.gov (United States)

    Sheng, Wen; Jiao, Xiaoli; He, Jifeng

    2007-12-01

    This paper presents a wavelet based hierarchical coding scheme for radar image compression. Radar signal is firstly quantized to digital signal, and reorganized as raster-scanned image according to radar's repeated period frequency. After reorganization, the reformed image is decomposed to image blocks with different frequency band by 2-D wavelet transformation, each block is quantized and coded by the Huffman coding scheme. A demonstrating system is developed, showing that under the requirement of real time processing, the compression ratio can be very high, while with no significant loss of target signal in restored radar image.

  20. Rhythm Synchronization of Coupled Neurons with Temporal Coding Scheme

    Institute of Scientific and Technical Information of China (English)

    SHI Xia; LU Qi-Shao

    2007-01-01

    Encoding information by firing patterns is one of the basic neural functions, and synchronization is important collective behaviour of a group of coupled neurons. Taking account of two schemes for encoding information (that is, rate coding and temporal coding), rhythm synchronization of coupled neurons is studied. There are two types of rhythm synchronization of neurons: spike and burst synchronizations. Firstly, it is shown that the spike synchronization is equivalent to the phase synchronization for coupled neurons. Secondly, the similarity function of the slow variables of neurons, which have relevant to the bursting process, is proposed to judge the burst synchronization. It is also found that the burst synchronization can be achieved more easily than the spike synchronization, whatever the firing patterns of the neurons are. Hence the temporal encoding scheme, which is closely related to both the spike and burst synchronizations, is more comprehensive than the rate coding scheme in essence.

  1. Quantum secure direct communication with frequency coding scheme

    Science.gov (United States)

    Zhao, Xue-Liang; Ruan, Dong

    2016-11-01

    Quantum secure direct communication (QSDC) is an important branch of quantum cryptography. It can transmit secret information directly without establishing a key first, unlike quantum key distribution which requires this precursive event. One of the most highlighted QSDC protocol is the Two-step protocol. This paper will focus on proposing a frequency coding scheme in the Two-step protocol, while retaining other contents of the QSDC protocol. This new coding scheme will significantly increase the protocol's ability against channel noise and loss, and provides an efficient protocol for secure direct quantum communication in a noisy environment. Besides, the frequency coding technology is also easy to understand and highly practical. After numerically simulating the performance of the protocol in a noisy channel, the results showed that the scheme was robust against channel noise and loss.

  2. An Efficient Attack on a Code-Based Signature Scheme

    OpenAIRE

    Phesso, Aurélie; Tillich, Jean-Pierre

    2016-01-01

    International audience; Baldi et al. have introduced in [BBC + 13] a very novel code based signature scheme. However we will prove here that some of the bits of the signatures are correlated in this scheme and this allows an attack that recovers enough of the underlying secret structure to forge new signatures. This cryptanalysis was performed on the parameters which were devised for 80 bits of security and broke them with 100, 000 signatures originating from the same secret key.

  3. Importance biasing scheme implemented in the PRIZMA code

    Energy Technology Data Exchange (ETDEWEB)

    Kandiev, I.Z.; Malyshkin, G.N. [Russian Federal Nuclear Center-All-Russia Scientific-Technical Inst. of Technical Physics, Snezhinsk (Russian Federation)

    1997-12-31

    PRIZMA code is intended for Monte Carlo calculations of linear radiation transport problems. The code has wide capabilities to describe geometry, sources, material composition, and to obtain parameters specified by user. There is a capability to calculate path of particle cascade (including neutrons, photons, electrons, positrons and heavy charged particles) taking into account possible transmutations. Importance biasing scheme was implemented to solve the problems which require calculation of functionals related to small probabilities (for example, problems of protection against radiation, problems of detection, etc.). The scheme enables to adapt trajectory building algorithm to problem peculiarities.

  4. Improved RB-HARQ scheme based on structured LDPC codes

    Institute of Scientific and Technical Information of China (English)

    WANG Wen-jun; LIN Yue-wei; YAN Yuan

    2007-01-01

    Reliability-based hybrid automatic repeat request (ARQ) (RB-HARQ) is a recently introduced approach to incremental-redundancy ARQ. In RB-HARQ scheme, the bits that are to be retransmitted are adaptively selected at the receiver based on the estimated bit reliability. It could result in significant performance gain but requires huge overhead in the feedback channel. In this study, an improved RB-HARQ scheme (IRB-HARQ) for structured low-density parity-check codes is proposed, which simplifies the comparison operations needed to search the bits to be retransmitted and outperforms the RB-HARQ scheme in consideration of the bit transmission power for the requesting messages on the feedback link. Simulation results show that the IRB-HARQ scheme is more efficient and practical than the RB-HARQ scheme.

  5. Development of outer-iteration free scheme for MATRA code

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Hyuk; Kim, S. J.; Park, J. P.; Hwang, D. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    The Picard scheme involves successive updating of the coefficient on the previously calculated values. The outer-iteration is terminated at that time being satisfied with boundary condition on which a lateral pressure difference between subchannels is even at exit plane. Diversion cross flow is generated to reduce the lateral pressure difference at each axial node. The physics can be numerically implemented with using approximation to force the lateral pressure difference to be the zero. The idea is firstly realized by prediction-correction method by C. Chiu. In this code, two-step method is adopted to approximate the lateral pressure difference term using diversion cross flow. The approximation allows the outer-iteration free scheme. The present study describes the implementation of outer-iteration free scheme, called non-iterative prediction-correction method into MATRA code. Outer-iteration free algorithm is implemented into the subchannel code MATRA. Original prediction-correction method applied only two channel is successfully expanded into the multichannel application. In comparison with the convectional outer-iteration numerical scheme, the present algorithm showed the more efficient and compatible accuracy on the verification problems, such as SMT- 5x5 problem and KSNP single assembly problem. In addition, outer-iteration free algorithm can be calculated in lower mass flow condition in which conventional scheme is breakdown.

  6. Locally decodable codes and private information retrieval schemes

    CERN Document Server

    Yekhanin, Sergey

    2010-01-01

    Locally decodable codes (LDCs) are codes that simultaneously provide efficient random access retrieval and high noise resilience by allowing reliable reconstruction of an arbitrary bit of a message by looking at only a small number of randomly chosen codeword bits. Local decodability comes with a certain loss in terms of efficiency - specifically, locally decodable codes require longer codeword lengths than their classical counterparts. Private information retrieval (PIR) schemes are cryptographic protocols designed to safeguard the privacy of database users. They allow clients to retrieve rec

  7. A Secure Code-Based Authentication Scheme for RFID Systems

    Directory of Open Access Journals (Sweden)

    Noureddine Chikouche

    2015-08-01

    Full Text Available Two essential problems are still posed in terms of Radio Frequency Identification (RFID systems, including: security and limitation of resources. Recently, Li et al.'s proposed a mutual authentication scheme for RFID systems in 2014, it is based on Quasi Cyclic-Moderate Density Parity Check (QC-MDPC McEliece cryptosystem. This cryptosystem is designed to reducing the key sizes. In this paper, we found that this scheme does not provide untraceability and forward secrecy properties. Furthermore, we propose an improved version of this scheme to eliminate existing vulnerabilities of studied scheme. It is based on the QC-MDPC McEliece cryptosystem with padding the plaintext by a random bit-string. Our work also includes a security comparison between our improved scheme and different code-based RFID authentication schemes. We prove secrecy and mutual authentication properties by AVISPA (Automated Validation of Internet Security Protocols and Applications tools. Concerning the performance, our scheme is suitable for low-cost tags with resource limitation.

  8. A Novel User Authentication Scheme Based on QR-Code

    Directory of Open Access Journals (Sweden)

    Kuan-Chieh Liao

    2010-08-01

    Full Text Available User authentication is one of the fundamental procedures to ensure secure communications and share system resources over an insecure public network channel.  Thus, a simple and efficient authentication mechanism is required for securing the network system in the real environment. In general, the password-based authentication mechanism provides the basic capability to prevent unauthorized access. Especially, the purpose of the one-time password is to make it more difficult to gain unauthorized access to restricted resources. Instead of using the password file as conventional authentication systems, many researchers have devoted to implement various one-time password schemes using smart cards, time-synchronized token or short message service in order to reduce the risk of tampering and maintenance cost.  However, these schemes are impractical because of the far from ubiquitous hardware devices or the infrastructure requirements. To remedy these weaknesses, the attraction of the QR-code technique can be introduced into our one-time password authentication protocol. Not the same as before, the proposed scheme based on QR code not only eliminates the usage of the password verification table, but also is a cost effective solution since most internet users already have mobile phones. For this reason, instead of carrying around a separate hardware token for each security domain, the superiority of handiness benefit from the mobile phone makes our approach more practical and convenient.

  9. A color-coded vision scheme for robotics

    Science.gov (United States)

    Johnson, Kelley Tina

    1991-01-01

    Most vision systems for robotic applications rely entirely on the extraction of information from gray-level images. Humans, however, regularly depend on color to discriminate between objects. Therefore, the inclusion of color in a robot vision system seems a natural extension of the existing gray-level capabilities. A method for robot object recognition using a color-coding classification scheme is discussed. The scheme is based on an algebraic system in which a two-dimensional color image is represented as a polynomial of two variables. The system is then used to find the color contour of objects. In a controlled environment, such as that of the in-orbit space station, a particular class of objects can thus be quickly recognized by its color.

  10. On codes, matroids and secure computation from linear secret sharing schemes

    NARCIS (Netherlands)

    Cramer, R.J.F.; Daza, V.; Gracia, J.L.; Jimenez Urroz, J.; Leander, G.; Marti-Farre, J.; Padro, C.

    2008-01-01

    Error-correcting codes and matroids have been widely used in the study of ordinary secret sharing schemes. In this paper, the connections between codes, matroids, and a special class of secret sharing schemes, namely, multiplicative linear secret sharing schemes (LSSSs), are studied. Such schemes ar

  11. The Penal Code (Amendment) Act 1989 (Act A727), 1989.

    Science.gov (United States)

    1989-01-01

    In 1989, Malaysia amended its penal code to provide that inducing an abortion is not an offense if the procedure is performed by a registered medical practitioner who has determined that continuation of the pregnancy would risk the life of the woman or damage her mental or physical health. Additional amendments include a legal description of the conditions which constitute the act of rape. Among these conditions is intercourse with or without consent with a woman under the age of 16. Malaysia fails to recognize rape within a marriage unless the woman is protected from her husband by judicial decree or is living separately from her husband according to Muslim custom. Rape is punishable by imprisonment for a term of 5-20 years and by whipping.

  12. A watermarking scheme for High Efficiency Video Coding (HEVC).

    Science.gov (United States)

    Swati, Salahuddin; Hayat, Khizar; Shahid, Zafar

    2014-01-01

    This paper presents a high payload watermarking scheme for High Efficiency Video Coding (HEVC). HEVC is an emerging video compression standard that provides better compression performance as compared to its predecessor, i.e. H.264/AVC. Considering that HEVC may will be used in a variety of applications in the future, the proposed algorithm has a high potential of utilization in applications involving broadcast and hiding of metadata. The watermark is embedded into the Quantized Transform Coefficients (QTCs) during the encoding process. Later, during the decoding process, the embedded message can be detected and extracted completely. The experimental results show that the proposed algorithm does not significantly affect the video quality, nor does it escalate the bitrate.

  13. A Joint-Coding Scheme With Crosstalk Avoidance in Network On Chip

    Directory of Open Access Journals (Sweden)

    Fen Ge

    2013-01-01

    Full Text Available The reliable transfer in Network on Chip can be guaranteed by crosstalk avoidance and error detection code. In this paper,we propose a joint coding scheme combined with crosstalk avoidance coding with error control coding. The Fibonacci numeral system is applied to satisfy the requirement of crosstalk avoidance coding, and the error detection is achieved by adding parity bits. We also implement the codec in register transfer level. Furthermore, the schemes of codec applying to fault-tolerant router are analyzed. The experimental result shows that "once encode, multiple decode" scheme outperforms other schemes in trade-o_ of delay, area and power.

  14. A MCTF video coding scheme based on distributed source coding principles

    Science.gov (United States)

    Tagliasacchi, Marco; Tubaro, Stefano

    2005-07-01

    Motion Compensated Temporal Filtering (MCTF) has proved to be an efficient coding tool in the design of open-loop scalable video codecs. In this paper we propose a MCTF video coding scheme based on lifting where the prediction step is implemented using PRISM (Power efficient, Robust, hIgh compression Syndrome-based Multimedia coding), a video coding framework built on distributed source coding principles. We study the effect of integrating the update step at the encoder or at the decoder side. We show that the latter approach allows to improve the quality of the side information exploited during decoding. We present the analytical results obtained by modeling the video signal along the motion trajectories as a first order auto-regressive process. We show that the update step at the decoder allows to half the contribution of the quantization noise. We also include experimental results with real video data that demonstrate the potential of this approach when the video sequences are coded at low bitrates.

  15. Probability of undetected error after decoding for a concatenated coding scheme

    Science.gov (United States)

    Costello, D. J., Jr.; Lin, S.

    1984-01-01

    A concatenated coding scheme for error control in data communications is analyzed. In this scheme, the inner code is used for both error correction and detection, however the outer code is used only for error detection. A retransmission is requested if the outer code detects the presence of errors after the inner code decoding. Probability of undetected error is derived and bounded. A particular example, proposed for NASA telecommand system is analyzed.

  16. Phase II evaluation of clinical coding schemes: completeness, taxonomy, mapping, definitions, and clarity. CPRI Work Group on Codes and Structures.

    Science.gov (United States)

    Campbell, J R; Carpenter, P; Sneiderman, C; Cohn, S; Chute, C G; Warren, J

    1997-01-01

    To compare three potential sources of controlled clinical terminology (READ codes version 3.1, SNOMED International, and Unified Medical Language System (UMLS) version 1.6) relative to attributes of completeness, clinical taxonomy, administrative mapping, term definitions and clarity (duplicate coding rate). The authors assembled 1929 source concept records from a variety of clinical information taken from four medical centers across the United States. The source data included medical as well as ample nursing terminology. The source records were coded in each scheme by an investigator and checked by the coding scheme owner. The codings were then scored by an independent panel of clinicians for acceptability. Codes were checked for definitions provided with the scheme. Codes for a random sample of source records were analyzed by an investigator for "parent" and "child" codes within the scheme. Parent and child pairs were scored by an independent panel of medical informatics specialists for clinical acceptability. Administrative and billing code mapping from the published scheme were reviewed for all coded records and analyzed by independent reviewers for accuracy. The investigator for each scheme exhaustively searched a sample of coded records for duplications. SNOMED was judged to be significantly more complete in coding the source material than the other schemes (SNOMED* 70%; READ 57%; UMLS 50%; *p < .00001). SNOMED also had a richer clinical taxonomy judged by the number of acceptable first-degree relatives per coded concept (SNOMED* 4.56, UMLS 3.17; READ 2.14, *p < .005). Only the UMLS provided any definitions; these were found for 49% of records which had a coding assignment. READ and UMLS had better administrative mappings (composite score: READ* 40.6%; UMLS* 36.1%; SNOMED 20.7%, *p < .00001), and SNOMED had substantially more duplications of coding assignments (duplication rate: READ 0%; UMLS 4.2%; SNOMED* 13.9%, *p < .004) associated with a loss of clarity

  17. On the Security of Digital Signature Schemes Based on Error-Correcting Codes

    NARCIS (Netherlands)

    Xu, Sheng-bo; Doumen, J.M.; van Tilborg, Henk

    We discuss the security of digital signature schemes based on error-correcting codes. Several attacks to the Xinmei scheme are surveyed, and some reasons given to explain why the Xinmei scheme failed, such as the linearity of the signature and the redundancy of public keys. Another weakness is found

  18. Group statistical channel coding dimming scheme in visible light communication system

    Science.gov (United States)

    Zhuang, Kaiyu; Huang, Zhitong; Zhang, Ruqi; Li, Jianfeng; Ji, Yuefeng

    2016-10-01

    In this paper, we propose a group statistical channel coding (GSCC) scheme, which achieves dimming by changing the ratio of the 0-1 symbol of the original data stream through probabilistic statistics method. The simulation under various brightness conditions displays that the GSCC maintains good performance comparing to PWM dimming with half satisfice of transmission rate and a larger dimming intensity. Simulation of GSCC after combining with other channel coding schemes reflects that GSCC has good compatibility to arbitrary access coded signal.

  19. Efficient image compression scheme based on differential coding

    Science.gov (United States)

    Zhu, Li; Wang, Guoyou; Liu, Ying

    2007-11-01

    Embedded zerotree (EZW) and Set Partitioning in Hierarchical Trees (SPIHT) coding, introduced by J.M. Shapiro and Amir Said, are very effective and being used in many fields widely. In this study, brief explanation of the principles of SPIHT was first provided, and then, some improvement of SPIHT algorithm according to experiments was introduced. 1) For redundancy among the coefficients in the wavelet region, we propose differential method to reduce it during coding. 2) Meanwhile, based on characteristic of the coefficients' distribution in subband, we adjust sorting pass and optimize differential coding, in order to reduce the redundancy coding in each subband. 3) The image coding result, calculated by certain threshold, shows that through differential coding, the rate of compression get higher, and the quality of reconstructed image have been get raised greatly, when bpp (bit per pixel)=0.5, PSNR (Peak Signal to Noise Ratio) of reconstructed image exceeds that of standard SPIHT by 0.2~0.4db.

  20. Multiple Schemes for Mobile Payment Authentication Using QR Code and Visual Cryptography

    Directory of Open Access Journals (Sweden)

    Jianfeng Lu

    2017-01-01

    Full Text Available QR code (quick response code is used due to its beneficial properties, especially in the mobile payment field. However, there exists an inevitable risk in the transaction process. It is not easily perceived that the attacker tampers with or replaces the QR code that contains merchant’s beneficiary account. Thus, it is of great urgency to conduct authentication of QR code. In this study, we propose a novel mechanism based on visual cryptography scheme (VCS and aesthetic QR code, which contains three primary schemes for different concealment levels. The main steps of these schemes are as follows. Firstly, one original QR code is split into two shadows using VC multiple rules; secondly, the two shadows are embedded into the same background image, respectively, and the embedded results are fused with the same carrier QR code, respectively, using XOR mechanism of RS and QR code error correction mechanism. Finally, the two aesthetic QR codes can be stacked precisely and the original QR code is restored according to the defined VCS. Experiments corresponding to three proposed schemes are conducted and demonstrate the feasibility and security of the mobile payment authentication, the significant improvement of the concealment for the shadows in QR code, and the diversity of mobile payment authentication.

  1. A New En-/de-coding Scheme of Spreading Time OCDMA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, we propose a new en-/de-coding scheme of spreading time OCDMA utilizing the dispersion of grating and filter in frequency domain. The key components of the scheme are grating pair, Fourier transformation lens, phase filter etc. The results of design and calculation are shown that the spreading time of input pulse can be up to nanosecond-duration and the phase filter can provide pseudo-noise bursts in time domain. The requirements for Laser and optical detection equipment in the scheme are reduced. So the new scheme proposed by us is effective for OCDMA en-/de-coding of coherent ultra-short pulses.

  2. An Asymmetric Fingerprinting Scheme based on Tardos Codes

    CERN Document Server

    Charpentier, Ana; Furon, Teddy; Cox, Ingemar

    2010-01-01

    Tardos codes are currently the state-of-the-art in the design of practical collusion-resistant fingerprinting codes. Tardos codes rely on a secret vector drawn from a publicly known probability distribution in order to generate each Buyer's fingerprint. For security purposes, this secret vector must not be revealed to the Buyers. To prevent an untrustworthy Provider forging a copy of a Work with an innocent Buyer's fingerprint, previous asymmetric fingerprinting algorithms enforce the idea of the Buyers generating their own fingerprint. Applying this concept to Tardos codes is challenging since the fingerprint must be based on this vector secret. This paper provides the first solution for an asymmetric fingerprinting protocol dedicated to Tardos codes. The motivations come from a new attack, in which an untrustworthy Provider by modifying his secret vector frames an innocent Buyer.

  3. CodeSlinger: a case study in domain-driven interactive tool design for biomedical coding scheme exploration and use.

    Science.gov (United States)

    Flowers, Natalie L

    2010-01-01

    CodeSlinger is a desktop application that was developed to aid medical professionals in the intertranslation, exploration, and use of biomedical coding schemes. The application was designed to provide a highly intuitive, easy-to-use interface that simplifies a complex business problem: a set of time-consuming, laborious tasks that were regularly performed by a group of medical professionals involving manually searching coding books, searching the Internet, and checking documentation references. A workplace observation session with a target user revealed the details of the current process and a clear understanding of the business goals of the target user group. These goals drove the design of the application's interface, which centers on searches for medical conditions and displays the codes found in the application's database that represent those conditions. The interface also allows the exploration of complex conceptual relationships across multiple coding schemes.

  4. Context-Adaptive Arithmetic Coding Scheme for Lossless Bit Rate Reduction of MPEG Surround in USAC

    Science.gov (United States)

    Yoon, Sungyong; Pang, Hee-Suk; Sung, Koeng-Mo

    We propose a new coding scheme for lossless bit rate reduction of the MPEG Surround module in unified speech and audio coding (USAC). The proposed scheme is based on context-adaptive arithmetic coding for efficient bit stream composition of spatial parameters. Experiments show that it achieves the significant lossless bit reduction of 9.93% to 12.14% for spatial parameters and 8.64% to 8.96% for the overall MPEG Surround bit streams compared to the original scheme. The proposed scheme, which is not currently included in USAC, can be used for the improved coding efficiency of MPEG Surround in USAC, where the saved bits can be utilized by the other modules in USAC.

  5. Scheme for implementing quantum dense coding with W-class state in cavity QED

    Institute of Scientific and Technical Information of China (English)

    He Juan; Ye Liu; Ni Zhi-Xiang

    2008-01-01

    An experimentally feasible protocol for realizing dense coding by using a class of W-state in cavity quantum electrodynamics (QED) is proposed in this paper.The prominent advantage of our scheme is that the succeasful probability of the dense coding with a W-class state can reach 1.In addition,the scheme can be implemented by the present cavity QED techniques.

  6. An Adaptive Video Coding Control Scheme for Real-Time MPEG Applications

    Directory of Open Access Journals (Sweden)

    Hsia Shih-Chang

    2003-01-01

    Full Text Available This paper proposes a new rate control scheme to increase the coding efficiency for MPEG systems. Instead of using a static group of picture (GOP structure, we present an adaptive GOP structure that uses more P- and B-frame coding, while the temporal correlation among the video frames maintains high. When there is a scene change, we immediately insert intramode coding to reduce the prediction error. Moreover, an enhanced prediction frame is used to improve the coding quality in the adaptive GOP. This rate control algorithm can both achieve better coding efficiency and solve the scene change problem. Even if the coding bit rate is over the predefined level, this coding scheme does not require re-encoding for real-time systems. Simulations demonstrate that our proposed algorithm can achieve better quality than TM5, and satisfactory reliability for detecting scene changes.

  7. A Contourlet-Based Embedded Image Coding Scheme on Low Bit-Rate

    Science.gov (United States)

    Song, Haohao; Yu, Songyu

    Contourlet transform (CT) is a new image representation method, which can efficiently represent contours and textures in images. However, CT is a kind of overcomplete transform with a redundancy factor of 4/3. If it is applied to image compression straightforwardly, the encoding bit-rate may increase to meet a given distortion. This fact baffles the coding community to develop CT-based image compression techniques with satisfactory performance. In this paper, we analyze the distribution of significant contourlet coefficients in different subbands and propose a new contourlet-based embedded image coding (CEIC) scheme on low bit-rate. The well-known wavelet-based embedded image coding (WEIC) algorithms such as EZW, SPIHT and SPECK can be easily integrated into the proposed scheme by constructing a virtual low frequency subband, modifying the coding framework of WEIC algorithms according to the structure of contourlet coefficients, and adopting a high-efficiency significant coefficient scanning scheme for CEIC scheme. The proposed CEIC scheme can provide an embedded bit-stream, which is desirable in heterogeneous networks. Our experiments demonstrate that the proposed scheme can achieve the better compression performance on low bit-rate. Furthermore, thanks to the contourlet adopted in the proposed scheme, more contours and textures in the coded images are preserved to ensure the superior subjective quality.

  8. COMPLEMENT BLOCK CODING SCHEME FOR REDUCING PEAK-TO-AVERAGE POWER RATIO OF OFDM SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    Jiang Tao; Zhu Guangxi

    2004-01-01

    A new scheme termed as Complement Block Coding (CBC) technique is proposed to reduce the Peak-to-Average Power Ratio (PAPR) of OFDM signals. Utilizing the complement bits which are added to the original information bits,this method can effectively reduce the PAPR of OFDM systems with random frame size N and the coding rate R ≤ (N - k)/N, where kis a positive integer and k ≤ N/2. The performance results obtained with CBC are given and compared with that of some well known schemes, such as Simple Block Coding (SBC), Modified Simple Block Coding (MSBC) and Simple Odd Parity Code (SOPC) for the same purpose. The results show that, at the same coding rate 3/4, the CBC can achieve almost the same performance as SBC, MSBC, but with lower complexity, and that the same performance can be obtained with higher coding rate by using CBC. At the same coding rate (N - 1)/N, the PAPR reduction of CBC is almost the twice as that of SOPC when N ≥ 16. Further more, the PAPR reductions with coding rate (N - 1)/N are almost the same as that with coding rate less than (N - 1)/N,so the proposed scheme CBC is more suitable for the large frame size with high coding rate and can provide error detection.

  9. QoS Based Capacity Enhancement for WCDMA Network with Coding Scheme

    CERN Document Server

    Ayyappan, K; 10.5121/vlsic.2010.1102

    2010-01-01

    The wide-band code division multiple access (WCDMA) based 3G and beyond cellular mobile wireless networks are expected to provide a diverse range of multimedia services to mobile users with guaranteed quality of service (QoS). To serve diverse quality of service requirements of these networks it necessitates new radio resource management strategies for effective utilization of network resources with coding schemes. Call admission control (CAC) is a significant component in wireless networks to guarantee quality of service requirements and also to enhance the network resilience. In this paper capacity enhancement for WCDMA network with convolutional coding scheme is discussed and compared with block code and without coding scheme to achieve a better balance between resource utilization and quality of service provisioning. The model of this network is valid for the real-time (RT) and non-real-time (NRT) services having different data rate. Simulation results demonstrate the effectiveness of the network using co...

  10. an Efficient Blind Signature Scheme based on Error Correcting Codes

    Directory of Open Access Journals (Sweden)

    Junyao Ye

    Full Text Available Cryptography based on the theory of error correcting codes and lattices has received a wide attention in the last years. Shor`s algorithm showed that in a world where quantum computers are assumed to exist, number theoretic cryptosystems are insecure. The ...

  11. Efficient rate control scheme for low bit rate H.264/AVC video coding

    Institute of Scientific and Technical Information of China (English)

    LI Zhi-cheng; ZHANG Yong-jun; LIU Tao; GU Wan-yi

    2009-01-01

    This article presents an efficient rate control scheme for H.264/AVC video coding in low bit rate environment. In the proposed scheme, an improved rate-distortion (RD) model by both analytical and empirical approaches is developed. It involves an enhanced mean absolute difference estimating method and a more rate-robust distortion model. Based on this RD model, an efficient macroblock-layer rate control scheme for H.264/AVC video coding is proposed. Experimental results show that this model encodes video sequences with higher peak signal-to-noise ratio gains and generates bit stream closer to the target rate.

  12. Hospital Coding Practice, Data Quality, and DRG-Based Reimbursement under the Thai Universal Coverage Scheme

    Science.gov (United States)

    Pongpirul, Krit

    2011-01-01

    In the Thai Universal Coverage scheme, hospital providers are paid for their inpatient care using Diagnosis Related Group (DRG) reimbursement. Questionable quality of the submitted DRG codes has been of concern whereas knowledge about hospital coding practice has been lacking. The objectives of this thesis are (1) To explore hospital coding…

  13. Hospital Coding Practice, Data Quality, and DRG-Based Reimbursement under the Thai Universal Coverage Scheme

    Science.gov (United States)

    Pongpirul, Krit

    2011-01-01

    In the Thai Universal Coverage scheme, hospital providers are paid for their inpatient care using Diagnosis Related Group (DRG) reimbursement. Questionable quality of the submitted DRG codes has been of concern whereas knowledge about hospital coding practice has been lacking. The objectives of this thesis are (1) To explore hospital coding…

  14. Huffman Coding with Letter Costs: A Linear-Time Approximation Scheme

    OpenAIRE

    Golin, Mordecai; Mathieu, Claire; Young, Neal E.

    2002-01-01

    We give a polynomial-time approximation scheme for the generalization of Huffman Coding in which codeword letters have non-uniform costs (as in Morse code, where the dash is twice as long as the dot). The algorithm computes a (1+epsilon)-approximate solution in time O(n + f(epsilon) log^3 n), where n is the input size.

  15. A channel differential EZW coding scheme for EEG data compression.

    Science.gov (United States)

    Dehkordi, Vahid R; Daou, Hoda; Labeau, Fabrice

    2011-11-01

    In this paper, a method is proposed to compress multichannel electroencephalographic (EEG) signals in a scalable fashion. Correlation between EEG channels is exploited through clustering using a k-means method. Representative channels for each of the clusters are encoded individually while other channels are encoded differentially, i.e., with respect to their respective cluster representatives. The compression is performed using the embedded zero-tree wavelet encoding adapted to 1-D signals. Simulations show that the scalable features of the scheme lead to a flexible quality/rate tradeoff, without requiring detailed EEG signal modeling.

  16. Coded-subcarrier-aided chromatic dispersion monitoring scheme for flexible optical OFDM networks.

    Science.gov (United States)

    Tse, Kam-Hon; Chan, Chun-Kit

    2014-08-11

    A simple coded-subcarrier aided scheme is proposed to perform chromatic dispersion monitoring in flexible optical OFDM networks. A pair of coded label subcarriers is added to both edges of the optical OFDM signal spectrum at the edge transmitter node. Upon reception at any intermediate or the receiver node, chromatic dispersion estimation is performed, via simple direct detection, followed by electronic correlation procedures with the designated code sequences. The feasibility and the performance of the proposed scheme have been experimentally characterized. It provides a cost-effective monitoring solution for the optical OFDM signals across intermediate nodes in flexible OFDM networks.

  17. Study on a new meteorological sampling scheme developed for the OSCAAR code system

    OpenAIRE

    Liu, X.; 富田 賢一; 本間 俊充

    2002-01-01

    One important step in Level 3 Probabilistic Safety Assessment is meteorological sequence sampling, on which the previous studies were mainly related to code systems using straight line plume model and more efforts are needed for trajectory puff model such as the OSCAAR code system. This report describes the development of a new meteorological sampling scheme for the OSCAAR code system that explicitly considers population distribution. A group of principles was set forth for the development of...

  18. An Efficient Code-Based Threshold Ring Signature Scheme with a Leader-Participant Model

    Directory of Open Access Journals (Sweden)

    Guomin Zhou

    2017-01-01

    Full Text Available Digital signature schemes with additional properties have broad applications, such as in protecting the identity of signers allowing a signer to anonymously sign a message in a group of signers (also known as a ring. While these number-theoretic problems are still secure at the time of this research, the situation could change with advances in quantum computing. There is a pressing need to design PKC schemes that are secure against quantum attacks. In this paper, we propose a novel code-based threshold ring signature scheme with a leader-participant model. A leader is appointed, who chooses some shared parameters for other signers to participate in the signing process. This leader-participant model enhances the performance because every participant including the leader could execute the decoding algorithm (as a part of signing process upon receiving the shared parameters from the leader. The time complexity of our scheme is close to Courtois et al.’s (2001 scheme. The latter is often used as a basis to construct other types of code-based signature schemes. Moreover, as a threshold ring signature scheme, our scheme is as efficient as the normal code-based ring signature.

  19. Cryptanalysis on AW digital signature scheme based on error-correcting codes

    Institute of Scientific and Technical Information of China (English)

    张振峰; 冯登国; 戴宗锋

    2002-01-01

    In 1993, Alabhadi and Wicker gave a modification to Xinmei Digital Signature Scheme based on error-correcting codes, which is usually denoted by AW Scheme. In this paper we show that the AW Scheme is actually not secure: anyone holding public keys of the signatory can obtain the equivalent private keys, and then forge digital signatures for arbitrary messages successfully. We also point out that one can hardly construct a digital signature scheme with high-level security due to the difficulty of decomposing large matrixes.

  20. A Distinguisher-Based Attack of a Homomorphic Encryption Scheme Relying on Reed-Solomon Codes

    CERN Document Server

    Gauthier, Valérie; Tillich, Jean-Pierre

    2012-01-01

    Bogdanov and Lee suggested a homomorphic public-key encryption scheme based on error correcting codes. The underlying public code is a modified Reed-Solomon code obtained from inserting a zero submatrix in the Vandermonde generating matrix defining it. The columns that define this submatrix are kept secret and form a set $L$. We give here a distinguisher that detects if one or several columns belong to $L$ or not. This distinguisher is obtained by considering the code generated by component-wise products of codewords of the public code (the so called "square code"). This operation is applied to punctured versions of this square code obtained by picking a subset $I$ of the whole set of columns. It turns out that the dimension of the punctured square code is directly related to the cardinality of the intersection of $I$ with $L$. This allows an attack which recovers the full set $L$ and which can then decrypt any ciphertext.

  1. GYRE: An open-source stellar oscillation code based on a new Magnus Multiple Shooting Scheme

    CERN Document Server

    Townsend, R H D

    2013-01-01

    We present a new oscillation code, GYRE, which solves the stellar pulsation equations (both adiabatic and non-adiabatic) using a novel Magnus Multiple Shooting numerical scheme devised to overcome certain weaknesses of the usual relaxation and shooting schemes appearing in the literature. The code is accurate (up to 6th order in the number of grid points), robust, efficiently makes use of multiple processor cores and/or nodes, and is freely available in source form for use and distribution. We verify the code against analytic solutions and results from other oscillation codes, in all cases finding good agreement. Then, we use the code to explore how the asteroseismic observables of a 1.5 M_sun star change as it evolves through the red-giant bump.

  2. A modified prediction scheme of the H.264 multiview video coding to improve the decoder performance

    Science.gov (United States)

    Hamadan, Ayman M.; Aly, Hussein A.; Fouad, Mohamed M.; Dansereau, Richard M.

    2013-02-01

    In this paper, we present a modified inter-view prediction scheme for the multiview video coding (MVC).With more inter-view prediction, the number of reference frames required to decode a single view increase. Consequently, the data size of decoding a single view increases, thus impacting the decoder performance. In this paper, we propose an MVC scheme that requires less inter-view prediction than that of the MVC standard scheme. The proposed scheme is implemented and tested on real multiview video sequences. Improvements are shown using the proposed scheme in terms of average data size required either to decode a single view, or to access any frame (i.e., random access), with comparable rate-distortion. It is compared to the MVC standard scheme and another improved techniques from the literature.

  3. Developing a Coding Scheme to Analyse Creativity in Highly-constrained Design Activities

    DEFF Research Database (Denmark)

    Dekoninck, Elies; Yue, Huang; Howard, Thomas J.;

    2010-01-01

    of design and analysis on a highly constrained design task. This paper shows how design changes can be coded using a scheme based on creative ‘modes of change’. The coding scheme can show the way a designer moves around the design space, and particularly the strategies that are used by a creative designer......This work is part of a larger project which aims to investigate the nature of creativity and the effectiveness of creativity tools in highly-constrained design tasks. This paper presents the research where a coding scheme was developed and tested with a designer-researcher who conducted two rounds...... to skip from one ‘train of solutions’ to new avenues. The coding scheme can be made more robust by: ensuring design change is always coded relative to a reference design; tightening up definitions of ‘system’, ‘element’ and ‘function’; and using a matrix to develop a more complete set of codes. A much...

  4. Nuclear Reactor Component Code CUPID-I: Numerical Scheme and Preliminary Assessment Results

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Hyoung Kyu; Jeong, Jae Jun; Park, Ik Kyu; Kim, Jong Tae; Yoon, Han Young

    2007-12-15

    A component scale thermal hydraulic analysis code, CUPID (Component Unstructured Program for Interfacial Dynamics), is being developed for the analysis of components of a nuclear reactor, such as reactor vessel, steam generator, containment, etc. It adopted three-dimensional, transient, two phase and three-field model. In order to develop the numerical schemes for the three-field model, various numerical schemes have been examined including the SMAC, semi-implicit ICE, SIMPLE, Row Scheme and so on. Among them, the ICE scheme for the three-field model was presented in the present report. The CUPID code is utilizing unstructured mesh for the simulation of complicated geometries of the nuclear reactor components. The conventional ICE scheme that was applied to RELAP5 and COBRA-TF, therefore, were modified for the application to the unstructured mesh. Preliminary calculations for the unstructured semi-implicit ICE scheme have been conducted for a verification of the numerical method from a qualitative point of view. The preliminary calculation results showed that the present numerical scheme is robust and efficient for the prediction of phase changes and flow transitions due to a boiling and a flashing. These calculation results also showed the strong coupling between the pressure and void fraction changes. Thus, it is believed that the semi-implicit ICE scheme can be utilized for transient two-phase flows in a component of a nuclear reactor.

  5. Underwater Acoustic Communication Based on Pattern Time Delay Shift Coding Scheme

    Institute of Scientific and Technical Information of China (English)

    YIN Jing-wei; HUI Jun-ying; HUI Juan; YAO Zhi-xiang; WANG Yi-lin

    2006-01-01

    Underwater acoustic communication based on Pattern Time Delay Shift Coding (PDS) communication scheme is studied. The time delay shift values of the pattern are used to encode the digital information in the PDS scheme, which belongs to the Pulse Position Modulation (PPM). The duty cycle of the PDS scheme is small, so it can economize the power for communication. By use of different patterns for code division and different frequencies for channel division, the communication system is capable of mitigating the inter-symbol interference (ISI) caused by the multipath channel. The data rate of communication is 1000 bits/s at 8 kHz bandwidth. The receiver separates the channels by means of band-pass filters, and performs decoding by 4 copy-correlators to estimate the time delay shift value. Based on the theoretical analysis and numerical simulations, the PDS scheme is shown to be a robust and effective approach for underwater acoustic communication.

  6. Novel UEP LT Coding Scheme with Feedback Based on Different Degree Distributions

    Directory of Open Access Journals (Sweden)

    Li Ya-Fang

    2016-01-01

    Full Text Available Traditional unequal error protection (UEP schemes have some limitations and problems, such as the poor UEP performance of high priority data and the seriously sacrifice of low priority data in decoding property. Based on the reasonable applications of different degree distributions in LT codes, this paper puts forward a novel UEP LT coding scheme with a simple feedback to compile these data packets separately. Simulation results show that the proposed scheme can effectively protect high priority data, and improve the transmission efficiency of low priority data from 2.9% to 22.3%. Furthermore, it is fairly suitable to apply this novel scheme to multicast and broadcast environments since only a simple feedback introduced.

  7. Performance of degree distribution based HARQ scheme for LDPC-coded OFDM system

    Institute of Scientific and Technical Information of China (English)

    LI Xue-hua; CAO Yi-qing; LI Zhen-song; YANG Da-cheng

    2009-01-01

    This article studies the degree distribution property of low density parity check (LDPC) codes by Gaussian approximation (GA) and presents an efficient hybrid automatic repeat quest (HARQ) scheme for LDPC-coded orthogonal frequency division multiplexing (OFDM) system. In the scheme, the important bits with large degrees have high retransmission priorities and are mapped to the sub-carriers with better channel quality indicator (CQI) levels in the OFDM system. The new scheme provides more protection to the bits with large degrees and thus contributes more to the decoding process by offering more transmission power. In this way the system performance would be improved. The statistics and simulation results also prove the new scheme.

  8. Two Schemes of Blind MMSE Multiuser Receiver for Space-Time Coded CDMA Systems

    Institute of Scientific and Technical Information of China (English)

    LU Min; XU Chang-jiang; FENG Guang-zeng

    2004-01-01

    Minimum Mean Square Error (MMSE) multiuser detection yields the highest output SINR among all linear detectors. The blind MMSE linear detector can be implemented with batch processes or sequential processes. In this paper, according to the different implementations of blind detectors, the authors analyze two schemes of the blind MMSE multiuser receiver for space-time coded CDMA Systems and make a comparison between both schemes by the theoretical analysis and numerical simulations.

  9. Efficient coding schemes with power allocation using space-time-frequency spreading

    Institute of Scientific and Technical Information of China (English)

    Jiang Haining; Luo Hanwen; Tian Jifeng; Song Wentao; Liu Xingzhao

    2006-01-01

    An efficient space-time-frequency (STF) coding strategy for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is presented for high bit rate data transmission over frequency selective fading channels. The proposed scheme is a new approach to space-time-frequency coded OFDM (COFDM) that combines OFDM with space-time coding, linear precoding and adaptive power allocation to provide higher quality of transmission in terms of the bit error rate performance and power efficiency. In addition to exploiting the maximum diversity gain in frequency, time and space, the proposed scheme enjoys high coding advantages and low-complexity decoding. The significant performance improvement of our design is confirmed by corroborating numerical simulations.

  10. Dense coding scheme using superpositions of Bell-states and its NMR implementation

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Jingfu; XIE; Jingyi; DENG; Zhiwei; LU; Zhiheng

    2005-01-01

    Dense coding using superpositions of Bell-states is proposed. The generalized Grover's algorithm is used to prepare the initial entangled states, and the reverse process of the quantum algorithm is used to determine the entangled state in the decoding measurement. Compared with the previous schemes, the superpositions of two Bell-states are exploited. Our scheme is demonstrated using a nuclear magnetic resonance (NMR)quantum computer. The corresponding manipulations are obtained. Experimental results show a good agreement between theory and experiment. We also generalize the scheme to transmit eight messages by introducing an additional two-state system.

  11. Code Division Multiplexing Using AI Based Custom Constellation Scheme - Efficient Modulation for High Data rate Transmission

    Directory of Open Access Journals (Sweden)

    K.SESHADRI SASTRY,

    2010-06-01

    Full Text Available To achieve high bit rate in transmission over wireless channels frequency reuse is an encouraging concept . Rather than dividing allocated frequency spectrum into narrow band width channels , one for each user information is transmitted over a very wide frequency spectrum using the same carrier frequency within same frequency band . In this paper we propose code division multiplexing scheme in which Custom QAM modulator itself is used as code . The propose system is simulated and tested in Matlab 7.4.

  12. QoS Based Capacity Enhancement for WCDMA Network with Coding Scheme

    Directory of Open Access Journals (Sweden)

    K.AYYAPPAN

    2010-03-01

    Full Text Available The wide-band code division multiple access (WCDMA based 3G and beyond cellular mobile wirelessnetworks are expected to provide a diverse range of multimedia services to mobile users withguaranteed quality of service (QoS. To serve diverse quality of service requirements of these networksit necessitates new radio resource management strategies for effective utilization of network resourceswith coding schemes. Call admission control (CAC is a significant component in wireless networks toguarantee quality of service requirements and also to enhance the network resilience. In this papercapacity enhancement for WCDMA network with convolutional coding scheme is discussed andcompared with block code and without coding scheme to achieve a better balance between resourceutilization and quality of service provisioning. The model of this network is valid for the real-time (RTand non-real-time (NRT services having different data rate. Simulation results demonstrate theeffectiveness of the network using convolutional code in terms of capacity enhancement and QoS of thevoice and video services.

  13. All-optical OFDM network coding scheme for all-optical virtual private communication in PON

    Science.gov (United States)

    Li, Lijun; Gu, Rentao; Ji, Yuefeng; Bai, Lin; Huang, Zhitong

    2014-03-01

    A novel optical orthogonal frequency division multiplexing (OFDM) network coding scheme is proposed over passive optical network (PON) system. The proposed scheme for all-optical virtual private network (VPN) does not only improve transmission efficiency, but also realize full-duplex communication mode in a single fiber. Compared with the traditional all-optical VPN architectures, the all-optical OFDM network coding scheme can support higher speed, more flexible bandwidth allocation, and higher spectrum efficiency. In order to reduce the difficulty of alignment for encoding operation between inter-communication traffic, the width of OFDM subcarrier pulse is stretched in our proposed scheme. The feasibility of all-optical OFDM network coding scheme for VPN is verified, and the relevant simulation results show that the full-duplex inter-communication traffic stream can be transmitted successfully. Furthermore, the tolerance of misalignment existing in inter-ONUs traffic is investigated and analyzed for all-optical encoding operation, and the difficulty of pulse alignment is proved to be lower.

  14. Codon sextets with leading role of serine create "ideal" symmetry classification scheme of the genetic code.

    Science.gov (United States)

    Rosandić, Marija; Paar, Vladimir

    2014-06-10

    The standard classification scheme of the genetic code is organized for alphabetic ordering of nucleotides. Here we introduce the new, "ideal" classification scheme in compact form, for the first time generated by codon sextets encoding Ser, Arg and Leu amino acids. The new scheme creates the known purine/pyrimidine, codon-anticodon, and amino/keto type symmetries and a novel A+U rich/C+G rich symmetry. This scheme is built from "leading" and "nonleading" groups of 32 codons each. In the ensuing 4 × 16 scheme, based on trinucleotide quadruplets, Ser has a central role as initial generator. Six codons encoding Ser and six encoding Arg extend continuously along a linear array in the "leading" group, and together with four of six Leu codons uniquely define construction of the "leading" group. The remaining two Leu codons enable construction of the "nonleading" group. The "ideal" genetic code suggests the evolution of genetic code with serine as an initiator. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Study on a new meteorological sampling scheme developed for the OSCAAR code system

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xinhe; Tomita, Kenichi; Homma, Toshimitsu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2002-03-01

    One important step in Level-3 Probabilistic Safety Assessment is meteorological sequence sampling, on which the previous studies were mainly related to code systems using the straight-line plume model and more efforts are needed for those using the trajectory puff model such as the OSCAAR code system. This report describes the development of a new meteorological sampling scheme for the OSCAAR code system that explicitly considers population distribution. A group of principles set for the development of this new sampling scheme includes completeness, appropriate stratification, optimum allocation, practicability and so on. In this report, discussions are made about the procedures of the new sampling scheme and its application. The calculation results illustrate that although it is quite difficult to optimize stratification of meteorological sequences based on a few environmental parameters the new scheme do gather the most inverse conditions in a single subset of meteorological sequences. The size of this subset may be as small as a few dozens, so that the tail of a complementary cumulative distribution function is possible to remain relatively static in different trials of the probabilistic consequence assessment code. (author)

  16. Complete Multiple Description Mesh-Based Video Coding Scheme and Its Performance

    Institute of Scientific and Technical Information of China (English)

    Yang-Li Wang; Cheng-Ke Wu

    2005-01-01

    This paper proposes a multiple description (MD) mesh-based motion coding method, which generates two descriptions for mesh-based motion by subsampling the nodes of a right-angled triangular mesh and dividing them into two groups. Motion vectors associated with the mesh nodes in each group are transmitted over distinct channels. With the nodes in each group, two other regular triangular meshes besides the original one can be constructed, and three different prediction images can be reconstructed according to descriptions available. The proposed MD mesh-based motion coding method is then combined with the pairwise correlating transform (PCT), and a complete MD video coding scheme is proposed. Further measures are taken to reduce the mismatch between the encoder and decoder that occurs when only one description is received and the decoder reconstruction is different from the encoder. The performance of the proposed scheme is evaluated using computer simulations, and the results show, compared to Reibman's MD transform coding (MDTC) method, the proposed scheme achieves better redundancy rate distortion (RRD) performance. In packet loss scenario, the proposed scheme outperforms the MDTC method.

  17. The DeMAND Coding Scheme: A Common Language for Representing and Analyzing Student Discourse

    Science.gov (United States)

    2010-01-01

    Convergent and discriminant validation by the multitrait-multimethod matrix. Psychological Bulletin, 56 (1959), 81-105. [8] J. Carletta, A. Isard , S... Isard , J. Kowtko, G. Doherty-Sneddon & A. Anderson, The reliability of a dialogue structure coding scheme. Computational Linguistics, 23 (1997), 13-32.

  18. A 3-layer coding scheme for biometry template protection based on spectral minutiae

    NARCIS (Netherlands)

    Shao, X.; Xu, H.; Veldhuis, Raymond N.J.; Slump, Cornelis H.

    2011-01-01

    Spectral Minutiae (SM) representation enables the combination of minutiae-based fingerprint recognition systems with template protection schemes based on fuzzy commitment, but it requires error-correcting codes that can handle high bit error rates (i.e. above 40%). In this paper, we propose a

  19. Delay-Aware Program Codes Dissemination Scheme in Internet of Everything

    Directory of Open Access Journals (Sweden)

    Yixuan Xu

    2016-01-01

    Full Text Available Due to recent advancements in big data, connection technologies, and smart devices, our environment is transforming into an “Internet of Everything” (IoE environment. These smart devices can obtain new or special functions by reprogramming: upgrade their soft systems through receiving new version of program codes. However, bulk codes dissemination suffers from large delay, energy consumption, and number of retransmissions because of the unreliability of wireless links. In this paper, a delay-aware program dissemination (DAPD scheme is proposed to disseminate program codes with fast, reliable, and energy-efficient style. We observe that although total energy is limited in wireless sensor network, there exists residual energy in nodes deployed far from the base station. Therefore, DAPD scheme improves the performance of bulk codes dissemination through the following two aspects. (1 Due to the fact that a high transmitting power can significantly improve the quality of wireless links, transmitting power of sensors with more residual energy is enhanced to improve link quality. (2 Due to the fact that performance of correlated dissemination tends to degrade in a highly dynamic environment, link correlation is autonomously updated in DAPD during codes dissemination to maintain improvements brought by correlated dissemination. Theoretical analysis and experimental results show that, compared with previous work, DAPD scheme improves the dissemination performance in terms of completion time, transmission cost, and the efficiency of energy utilization.

  20. Efficient spread space-time block coding scheme in multiple antenna systems

    Institute of Scientific and Technical Information of China (English)

    Qiu Ling; Zheng Xiayu

    2006-01-01

    Space-time coding is an important technique that can improve transmission performance at fading environments in mobile communication systems. In this paper, we propose a novel diversity scheme using spread spacetime block coding (SSTBC) in multiple antenna systems. At the transmitter, the primitive data are serial to parallel converted to multiple data streams, and each stream is rotated in constellation. Then Walsh codes are used to spread each symbol to all antenna space in a space-time block. The signals received from all receiver antennas are combined with the maximum ratio combining (MRC), equalized with linear equalizer to eliminate the inter-code interference and finally demodulated to recover to transmit data by using the one-symbol maximum likelihood detector. The proposed scheme does not sacrifice the spectrum efficiency meanwhile maintains the transceiver with low complexity. Owing to the transmission symbols of different transmit antennas passing through all the spatial subchannels between transceiver antenna pairs, the system obtains the partial additional space diversity gain of all spatial paths. It is also shown that the diversity gain is better than the previous space-time block coding (STBC) schemes with full transmission rate.

  1. A Study on Architecture of Malicious Code Blocking Scheme with White List in Smartphone Environment

    Science.gov (United States)

    Lee, Kijeong; Tolentino, Randy S.; Park, Gil-Cheol; Kim, Yong-Tae

    Recently, the interest and demands for mobile communications are growing so fast because of the increasing prevalence of smartphones around the world. In addition, the existing feature phones were replaced by smartphones and it has widely improved while using the explosive growth of Internet users using smartphones, e-commerce enabled Internet banking transactions and the importance of protecting personal information. Therefore, the development of smartphones antivirus products was developed and launched in order to prevent malicious code or virus infection. In this paper, we proposed a new scheme to protect the smartphone from malicious codes and malicious applications that are element of security threats in mobile environment and to prevent information leakage from malicious code infection. The proposed scheme is based on the white list smartphone application which only allows installing authorized applications and to prevent the installation of malicious and untrusted mobile applications which can possibly infect the applications and programs of smartphones.

  2. Optical schemes for speckle suppression by Barker code diffractive optical elements.

    Science.gov (United States)

    Lapchuk, A; Kryuchyn, A; Petrov, V; Shyhovets, O V; Pashkevich, G A; Bogdan, O V; Kononov, A; Klymenko, A

    2013-09-01

    A method for speckle suppression based on Barker code and M-sequence code diffractive optical elements (DOEs) is analyzed. An analytical formula for the dependence of speckle contrast on the wavelength of the laser illumination is derived. It is shown that speckle contrast has a wide maximum around the optimal wavelength that makes it possible to obtain large speckle suppression by using only one DOE for red, green, and blue laser illumination. Optical schemes for implementing this method are analyzed. It is shown that the method can use a simple liquid-crystal panel for phase rotation instead of a moving DOE; however, this approach requires a high frequency of liquid-crystal switching. A simple optical scheme is proposed using a 1D Barker code DOE and a simple 1D liquid-crystal panel, which does not require a high frequency of liquid-crystal switching or high-accuracy DOE movement.

  3. Practical Entanglement Distillation Scheme Using Recurrence Method And Quantum Low Density Parity Check Codes

    CERN Document Server

    Chau, H F

    2009-01-01

    Many entanglement distillation schemes use either universal random hashing or breading as their final step to obtain shared almost perfect EPR pairs. Both methods involve random stabilizer quantum error-correcting codes whose syndromes can be measured using simple and efficient quantum circuits. When applied to high fidelity Werner states, the highest yield protocol among those using local Bell measurements and local unitary operations is the one that uses a certain breading method. And random hashing method losses to breading just by a thin margin. In spite of their high yield, the hardness of decoding random linear code makes the use of random hashing and breading infeasible in practice. In this pilot study, we analyze the performance of recurrence method, a well-known entanglement distillation scheme, by replacing the final random hashing or breading procedure by various efficiently decodable quantum codes. We find that among all the replacements we have investigated, the one using a certain adaptive quant...

  4. Coding and Allocation for Distributed Data Storage: Fundamental Tradeoffs, Coding Schemes and Allocation Patterns

    OpenAIRE

    Andriyanova, Iryna

    2013-01-01

    Doctoral; Distributed storage is one of the most actively developing topics nowadays, thanks to the growing need of storing more and more large amounts of data and to new distributed applications as cloud computing, multimedia content delivery etc. The core of each distributed storage system (DSS) is its erasure-correcting code; the core of the DSS networking protocol is its allocation pattern.With new aforementioned storage applications we are about to attain the limit of well-developed codi...

  5. Parallel coding schemes of whisker velocity in the rat's somatosensory system.

    Science.gov (United States)

    Lottem, Eran; Gugig, Erez; Azouz, Rony

    2015-03-15

    The function of rodents' whisker somatosensory system is to transform tactile cues, in the form of vibrissa vibrations, into neuronal responses. It is well established that rodents can detect numerous tactile stimuli and tell them apart. However, the transformation of tactile stimuli obtained through whisker movements to neuronal responses is not well-understood. Here we examine the role of whisker velocity in tactile information transmission and its coding mechanisms. We show that in anaesthetized rats, whisker velocity is related to the radial distance of the object contacted and its own velocity. Whisker velocity is accurately and reliably coded in first-order neurons in parallel, by both the relative time interval between velocity-independent first spike latency of rapidly adapting neurons and velocity-dependent first spike latency of slowly adapting neurons. At the same time, whisker velocity is also coded, although less robustly, by the firing rates of slowly adapting neurons. Comparing first- and second-order neurons, we find similar decoding efficiencies for whisker velocity using either temporal or rate-based methods. Both coding schemes are sufficiently robust and hardly affected by neuronal noise. Our results suggest that whisker kinematic variables are coded by two parallel coding schemes and are disseminated in a similar way through various brain stem nuclei to multiple brain areas. Copyright © 2015 the American Physiological Society.

  6. Multilevel Coding Schemes for Compute-and-Forward with Flexible Decoding

    CERN Document Server

    Hern, Brett

    2011-01-01

    We consider the design of coding schemes for the wireless two-way relaying channel when there is no channel state information at the transmitter. In the spirit of the compute and forward paradigm, we present a multilevel coding scheme that permits computation (or, decoding) of a class of functions at the relay. The function to be computed (or, decoded) is then chosen depending on the channel realization. We define such a class of functions which can be decoded at the relay using the proposed coding scheme and derive rates that are universally achievable over a set of channel gains when this class of functions is used at the relay. We develop our framework with general modulation formats in mind, but numerical results are presented for the case where each node transmits using the QPSK constellation. Numerical results with QPSK show that the flexibility afforded by our proposed scheme results in substantially higher rates than those achievable by always using a fixed function or by adapting the function at the ...

  7. Towards a Fair and Efficient Packet Scheduling Scheme in Inter-Flow Network Coding

    Directory of Open Access Journals (Sweden)

    Jin Wang

    2014-11-01

    Full Text Available Network coding techniques are usually applied upon network-layer protocols to improve throughput in wireless networks. In scenarios with multiple unicast sessions, fairness is also an important factor. Therefore, a network coding-aware packet-scheduling algorithm is required. A packet-scheduling algorithm determines which packet to send next from a node’s packet backlog. Existing protocols mostly employ a basic round-robin scheduling algorithm to give “equal” opportunities to different packet flows. In fact, this “equal”-opportunity scheduling is neither fair, nor efficient. This paper intends to accentuate the importance of a coding-aware scheduling scheme. With a good scheduling scheme, we can gain more control over the per-flow throughput and fairness. Specifically, we first formulate a static scheduling problem and propose an algorithm to find the optimal scheduling scheme. We then extend the technique to a dynamic setting and, later, to practical routing protocols. Results show that the algorithm is comparatively scalable, and it can improve the throughput gain when the network is not severely saturated. The fairness among flows is drastically improved as a result of this scheduling scheme.

  8. Color coded multiple access scheme for bidirectional multiuser visible light communications in smart home technologies

    Science.gov (United States)

    Tiwari, Samrat Vikramaditya; Sewaiwar, Atul; Chung, Yeon-Ho

    2015-10-01

    In optical wireless communications, multiple channel transmission is an attractive solution to enhancing capacity and system performance. A new modulation scheme called color coded multiple access (CCMA) for bidirectional multiuser visible light communications (VLC) is presented for smart home applications. The proposed scheme uses red, green and blue (RGB) light emitting diodes (LED) for downlink and phosphor based white LED (P-LED) for uplink to establish a bidirectional VLC and also employs orthogonal codes to support multiple users and devices. The downlink transmission for data user devices and smart home devices is provided using red and green colors from the RGB LEDs, respectively, while uplink transmission from both types of devices is performed using the blue color from P-LEDs. Simulations are conducted to verify the performance of the proposed scheme. It is found that the proposed bidirectional multiuser scheme is efficient in terms of data rate and performance. In addition, since the proposed scheme uses RGB signals for downlink data transmission, it provides flicker-free illumination that would lend itself to multiuser VLC system for smart home applications.

  9. Hybrid threshold adaptable quantum secret sharing scheme with reverse Huffman-Fibonacci-tree coding

    Science.gov (United States)

    Lai, Hong; Zhang, Jun; Luo, Ming-Xing; Pan, Lei; Pieprzyk, Josef; Xiao, Fuyuan; Orgun, Mehmet A.

    2016-08-01

    With prevalent attacks in communication, sharing a secret between communicating parties is an ongoing challenge. Moreover, it is important to integrate quantum solutions with classical secret sharing schemes with low computational cost for the real world use. This paper proposes a novel hybrid threshold adaptable quantum secret sharing scheme, using an m-bonacci orbital angular momentum (OAM) pump, Lagrange interpolation polynomials, and reverse Huffman-Fibonacci-tree coding. To be exact, we employ entangled states prepared by m-bonacci sequences to detect eavesdropping. Meanwhile, we encode m-bonacci sequences in Lagrange interpolation polynomials to generate the shares of a secret with reverse Huffman-Fibonacci-tree coding. The advantages of the proposed scheme is that it can detect eavesdropping without joint quantum operations, and permits secret sharing for an arbitrary but no less than threshold-value number of classical participants with much lower bandwidth. Also, in comparison with existing quantum secret sharing schemes, it still works when there are dynamic changes, such as the unavailability of some quantum channel, the arrival of new participants and the departure of participants. Finally, we provide security analysis of the new hybrid quantum secret sharing scheme and discuss its useful features for modern applications.

  10. A New Decoding Scheme for Errorless Codes for Overloaded CDMA with Active User Detection

    CERN Document Server

    Mousavi, Ali; Marvasti, Farokh

    2010-01-01

    Recently, a new class of binary codes for overloaded CDMA systems are proposed that not only has the ability of errorless communication but also suitable for detecting active users. These codes are called COWDA [1]. In [1], a Maximum Likelihood (ML) decoder is proposed for this class of codes. Although the proposed scheme of coding/decoding show impressive performance, the decoder can be improved. In this paper by assuming more practical conditions for the traffic in the system, we suggest an algorithm that increases the performance of the decoder several orders of magnitude (the Bit-Error-Rate (BER) is divided by a factor of 400 in some Eb/N0's The algorithm supposes the Poison distribution for the time of activation/deactivation of the users.

  11. A qualitative study of DRG coding practice in hospitals under the Thai Universal Coverage Scheme

    Directory of Open Access Journals (Sweden)

    Winch Peter J

    2011-04-01

    Full Text Available Abstract Background In the Thai Universal Coverage health insurance scheme, hospital providers are paid for their inpatient care using Diagnosis Related Group-based retrospective payment, for which quality of the diagnosis and procedure codes is crucial. However, there has been limited understandings on which health care professions are involved and how the diagnosis and procedure coding is actually done within hospital settings. The objective of this study is to detail hospital coding structure and process, and to describe the roles of key hospital staff, and other related internal dynamics in Thai hospitals that affect quality of data submitted for inpatient care reimbursement. Methods Research involved qualitative semi-structured interview with 43 participants at 10 hospitals chosen to represent a range of hospital sizes (small/medium/large, location (urban/rural, and type (public/private. Results Hospital Coding Practice has structural and process components. While the structural component includes human resources, hospital committee, and information technology infrastructure, the process component comprises all activities from patient discharge to submission of the diagnosis and procedure codes. At least eight health care professional disciplines are involved in the coding process which comprises seven major steps, each of which involves different hospital staff: 1 Discharge Summarization, 2 Completeness Checking, 3 Diagnosis and Procedure Coding, 4 Code Checking, 5 Relative Weight Challenging, 6 Coding Report, and 7 Internal Audit. The hospital coding practice can be affected by at least five main factors: 1 Internal Dynamics, 2 Management Context, 3 Financial Dependency, 4 Resource and Capacity, and 5 External Factors. Conclusions Hospital coding practice comprises both structural and process components, involves many health care professional disciplines, and is greatly varied across hospitals as a result of five main factors.

  12. Optical Code-Division Multiple-Access and Wavelength Division Multiplexing: Hybrid Scheme Review

    Directory of Open Access Journals (Sweden)

    P. Susthitha Menon

    2012-01-01

    Full Text Available Problem statement: Hybrid Optical Code-Division Multiple-Access (OCDMA and Wavelength-Division Multiplexing (WDM have flourished as successful schemes for expanding the transmission capacity as well as enhancing the security for OCDMA. However, a comprehensive review related to this hybrid system are lacking currently. Approach: The purpose of this paper is to review the literature on OCDMA-WDM overlay systems, including our hybrid approach of one-dimensional coding of SAC OCDMA with WDM signals. In addition, we present an additional review of other categorios of hybrid WDM/OCDMA schemes, where codes of OCDMA can be employed on each WDM wavelength. Furthermore, an essential background of OCDMA, recent coding techniques and security issues are also presented. Results: Our results indicate that the feasibility of transmitting both OCDMA and WDM users on the same spectrum band can be achieved using MQC family code with an acceptable performance as well as good data confidentiality. In addition, the WDM interference signals can be suppressed properly for detection of optical broadband CDMA using notch filters. Conclusion: The paper provides a comprehensive overview of hybrid OCDMA-WDM systems and can be used as a baseline study for other scientists in the similar scope of research.

  13. Block-Based Adaptive Vector Lifting Schemes for Multichannel Image Coding

    Directory of Open Access Journals (Sweden)

    Amel Benazza-Benyahia

    2007-04-01

    Full Text Available We are interested in lossless and progressive coding of multispectral images. To this respect, nonseparable vector lifting schemes are used in order to exploit simultaneously the spatial and the interchannel similarities. The involved operators are adapted to the image contents thanks to block-based procedures grounded on an entropy optimization criterion. A vector encoding technique derived from EZW allows us to further improve the efficiency of the proposed approach. Simulation tests performed on remote sensing images show that a significant gain in terms of bit rate is achieved by the resulting adaptive coding method with respect to the non-adaptive one.

  14. Block-Based Adaptive Vector Lifting Schemes for Multichannel Image Coding

    Directory of Open Access Journals (Sweden)

    Pesquet Jean-Christophe

    2007-01-01

    Full Text Available We are interested in lossless and progressive coding of multispectral images. To this respect, nonseparable vector lifting schemes are used in order to exploit simultaneously the spatial and the interchannel similarities. The involved operators are adapted to the image contents thanks to block-based procedures grounded on an entropy optimization criterion. A vector encoding technique derived from EZW allows us to further improve the efficiency of the proposed approach. Simulation tests performed on remote sensing images show that a significant gain in terms of bit rate is achieved by the resulting adaptive coding method with respect to the non-adaptive one.

  15. Fountain code-based error control scheme for dimmable visible light communication systems

    Science.gov (United States)

    Feng, Lifang; Hu, Rose Qingyang; Wang, Jianping; Xu, Peng

    2015-07-01

    In this paper, a novel error control scheme using Fountain codes is proposed in on-off keying (OOK) based visible light communications (VLC) systems. By using Fountain codes, feedback information is needed to be sent back to the transmitter only when transmitted messages are successfully recovered. Therefore improved transmission efficiency, reduced protocol complexity and relative little wireless link-layer delay are gained. By employing scrambling techniques and complementing symbols, the least complemented symbols are needed to support arbitrary dimming target values, and the value of entropy of encoded message are increased.

  16. BLOCK CODING SCHEME FOR REDUCING PAPR IN OFDM SYSTEMS WITH LARGE NUMBER OF SUBCARRIERS

    Institute of Scientific and Technical Information of China (English)

    Jiang Tao; Zhu Guangxi; Zheng Jianbin

    2004-01-01

    The major drawback in Orthogonal Frequency Division Multiplexing (OFDM) system is due to the high Peak-to-Average Power Ratio (PAPR), so the performance of the system is significantly degraded by the nonlinearity of a High Power Amplifier (HPA) in the transmitter.In order to mitigate distortion, a block coding scheme for reducing PAPR in OFDM systems with large number of subcarriers based on complementary sequences and predistortion is proposed,which is capable of both error correction and PAPR reduction. Computer simulation results show that the proposed scheme significantly improves Bit Error Rate(BER) performance as compared to an uncoded system when an HPA is employed or a coded system without predistortion.

  17. An Enforceable Incentive Scheme in Wireless Multi-path Inter-session Network Coding Game

    Directory of Open Access Journals (Sweden)

    Zhuoqun Xia

    2012-02-01

    Full Text Available There are some selfish nodes in wireless mesh networks multi-path inter-session network coding; and all selfish nodes maximize their earnings through the game. In this paper, a stimulus scheme is proposed which is suit for selfish nodes game in a multi-path inter-session network coding game. In the multi-path transmission, we use the watch dog checks the existence of selfish nodes. After selfish nodes are detected, we modified the multi-path protocols. For multi-path selfish nodes, we adopt non-cooperation method to punish it; and that the priority forwarding is used to active cooperation nodes. It is proved that Nash equilibrium is acquired for all players to obey the incentive scheme honestly. Experiments verify the theoretical analysis.

  18. Distortion Modeling and Error Robust Coding Scheme for H.26L Video

    Institute of Scientific and Technical Information of China (English)

    CHENChuan; YUSongyu; CHENGLianji

    2004-01-01

    Transmission of hybrid-coded video including motion compensation and spatial prediction over error prone channel results in the well-known problem of error propagation because of the drift in reference frames between encoder and decoder. The prediction loop propa-gates errors and causes substantial degradation in video quality. Especially in H.26L video, both intra and inter prediction strategies are used to improve compression efficiency, however, they make error propagation more serious. This work proposes distortion models for H.26L video to optimally estimate the overall distortion of decoder frame reconstruction due to quantization, error propagation, and error concealment. Based on these statistical distortion models, our error robust coding scheme only integrates the distinct distortion between intra and inter macroblocks into a rate-distortlon based framework to select suitable coding mode for each macroblock, and so,the cost in computation complexity is modest. Simulations under typical 3GPP/3GPP2 channel and Internet channel conditions have shown that our proposed scheme achieves much better performance than those currently used in H.26L. The error propagation estimation and effect at high fractural pixel-level prediction have also been tested. All the results have demonstrated that our proposed scheme achieves a good balance between compression efficiency and error robustness for H.26L video, at the cost of modest additional complexity.

  19. A Coding Scheme Development Methodology Using Grounded Theory For Qualitative Analysis Of Pair Programming

    Directory of Open Access Journals (Sweden)

    Stephan Salinger

    2008-01-01

    Full Text Available A number of quantitative studies of pair programming (the practice of two programmers working together using just one computer have partially conflicting results. Qualitative studies are needed to explain what is really going on. We support such studies by taking a grounded theory (GT approach for deriving a coding scheme for the objective conceptual description of specific pair programming sessions independent of a particular research goal. The present article explains why our initial attempts at using GT failed and describes how to avoid these difficulties by a predetermined perspective on the data, concept naming rules, an analysis results metamodel, and pair coding. These practices may be helpful in all GT situations, particularly those involving very rich data such as video data. We illustrate the operation and usefulness of these practices by real examples derived from our coding work and present a few preliminary hypotheses regarding pair programming that have surfaced.

  20. On the Need of Novel Medium Access Control Schemes for Network Coding enabled Wireless Mesh Networks

    DEFF Research Database (Denmark)

    Paramanathan, Achuthan; Pahlevani, Peyman; Roetter, Daniel Enrique Lucani;

    2013-01-01

    This paper advocates for a new Medium Access Control (MAC) strategy for wireless meshed networks by identifying overload scenarios in order to provide additional channel access priority to the relay. The key behind our MAC protocol is that the relay will adjust its back off window size according...... to the incoming and outgoing packet ratio. We describe the new protocol as an extension to the CSMA/CA protocol and implement the protocol on our own hardware platform. By means of our own testbed, we investigate two basic network structures, namely, the two-way relay and the cross topology. It is well known...... that network coding will improve the throughput in such systems, but our novel medium access scheme improves the performance in the cross topology by another 66 % for network coding and 150 % for classical forwarding in theory. These gains translate in a theoretical gain of 33 % of network coding over...

  1. Development of orthogonal 2-dimensional numerical code TFC2D for fluid flow with various turbulence models and numerical schemes

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ju Yeop; In, Wang Kee; Chun, Tae Hyun; Oh, Dong Seok [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2000-02-01

    The development of orthogonal 2-dimensional numerical code is made. The present code contains 9 kinds of turbulence models that are widely used. They include a standard k-{epsilon} model and 8 kinds of low Reynolds number ones. They also include 6 kinds of numerical schemes including 5 kinds of low order schemes and 1 kind of high order scheme such as QUICK. To verify the present numerical code, pipe flow, channel flow and expansion pipe flow are solved by this code with various options of turbulence models and numerical schemes and the calculated outputs are compared to experimental data. Furthermore, the discretization error that originates from the use of standard k-{epsilon} turbulence model with wall function is much more diminished by introducing a new grid system than a conventional one in the present code. 23 refs., 58 figs., 6 tabs. (Author)

  2. A Chaos MIMO Transmission Scheme for Channel Coding and Physical-Layer Security

    Science.gov (United States)

    Okamoto, Eiji

    In recent wireless communication systems, security is ensured mainly in the upper-layer techniques such as a password or a cryptography processing. However, security needs not be restricted to the upper-layer and the addition of physical-layer security also would yield a much more robust system. Therefore, in this paper, we exploit chaos communication and propose a chaos multiple-input multiple-output (MIMO) transmission scheme which achieves physical-layer security and additional channel-coding gain. A chaotic modulation symbol is multiplied to the data to be transmitted at each MIMO antenna to exploit the MIMO antenna diversity, and at the receiver, the joint MIMO detection and chaos decoding is done by maximum likelihood decoding (MLD). The conventional chaos modulation suffers from bit error rate (BER) performance degradation, while the coding gain is obtained in the proposed scheme by the chaos modulation in MIMO. We evaluate the performances of the proposed scheme by an analysis and computer simulations.

  3. A New Quantum Key Distribution Scheme Based on Frequency and Time Coding

    Institute of Scientific and Technical Information of China (English)

    ZHU Chang-Hua; PEI Chang-Xing; QUAN Dong-Xiao; GAO Jing-Liang; CHEN Nan; YI Yun-Hui

    2010-01-01

    @@ A new scheme of quantum key distribution (QKD) using frequency and time coding is proposed,in which the security is based on the frequency-time uncertainty relation.In this scheme,the binary information sequence is encoded randomly on either the central frequency or the time delay of the optical pulse at the sender.The central frequency of the single photon pulse is set as ω1 for bit 0 and set as ω2 for bit 1 when frequency coding is selected.However,the single photon pulse is not delayed for bit 0 and is delayed in T for 1 when time coding is selected.At the receiver,either the frequency or the time delay of the pulse is measured randomly,and the final key is obtained after basis comparison,data reconciliation and privacy amplification.With the proposed method,the effect of the noise in the fiber channel and environment on the QKD system can be reduced effectively.

  4. A Real Orthogonal Space-Time Coded UWB Scheme for Wireless Secure Communications

    Directory of Open Access Journals (Sweden)

    Zhang Yanbing

    2009-01-01

    Full Text Available Recent research reveals that information security and information-hiding capabilities can be enhanced by proper exploitation of space-time techniques. Meanwhile, intrinsic properties of ultra-wideband (UWB signals make it an outstanding candidate for secure applications. In this paper, we propose a space-time coding scheme for impulse radio UWB systems. A novel real orthogonal group code is designed for multi-antenna UWB signals to exploit the full spatial diversity gain and achieve the perfect communication secrecy. Its performance in a frequency-selective fading channel is analyzed. The transmission secrecy, including low probability of detection (LPD, low probability of intercept (LPI, and anti-jamming performance, is investigated, and some fundamental tradeoffs between these secrecy metrics are also addressed. A comparison of the proposed scheme with the direct sequence spread spectrum (DSSS technique is carried out, which demonstrates that proper combination of UWB and space-time coding can provide substantial enhancement to wireless secure communications over other concurrent systems.

  5. Enhancing spoken connected-digit recognition accuracy by error correction codes – A novel scheme

    Indian Academy of Sciences (India)

    Sunil K Kopparapu; P V S Rao

    2004-10-01

    Recognizing spoken connected-digit numbers accurately is an important problem and has very many applications. Though state-of-the-art word recognition systems have gained acceptable accuracy levels, the accuracy of recognition of current connected spoken digits (and other short words) is very poor. In this paper, we develop a novel scheme to enhance the accuracy of recognizing a connected number. The basic idea proposed in this paper is to increase the number of digits in a number and use these appended digits to increase the overall accuracy of recognizing the number, as is done in the error-correcting code literature. We further show that the developed scheme is able to uniquely and exactly correct single-digit errors.

  6. AN ERROR-RESILIENT H.263+ CODING SCHEME FOR VIDEO TRANSMISSION OVER WIRELESS NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Li Jian; Bie Hongxia

    2006-01-01

    Video transmission over wireless networks has received much attention recently for its restricted bandwidth and high bit-error rate. Based on H.263+, by reversing part stream sequences of each Group Of Block (GOB), an error resilient scheme is presented to improve video robustness without additional bandwidth burden. Error patterns are employed to simulate Wideband Code Division Multiple Access(WCDMA) channels to check out error resilience performances. Simulation results show that both subjective and objective qualities of the reconstructed images are improved remarkably. The mean Peak Signal to Noise Ratio (PSNR)is increased by 0.5dB, and the highest increment is 2dB.

  7. Scheme for implementing quantum dense coding with four-particle decoherence-free states in an ion trap

    Institute of Scientific and Technical Information of China (English)

    Zheng Xiao-Juan; Cao Shuai; Fang Mao-Fa; Liao Xiang-Ping

    2008-01-01

    This paper proposes an experimentally feasible scheme for implementing quantum dense coding of trapped-ion system in decoherence-free states.As the phase changes due to time evolution of components with different eigenenergies of quantum superposition are completely frozen,quantum dense coding based on this model would be perfect.The scheme is insensitive to heating of vibrational mode and Bell states can be exactly distinguished via detecting the ionic state.

  8. Alternative Line Coding Scheme with Fixed Dimming for Visible Light Communication

    Science.gov (United States)

    Niaz, M. T.; Imdad, F.; Kim, H. S.

    2017-01-01

    An alternative line coding scheme called fixed-dimming on/off keying (FD-OOK) is proposed for visible-light communication (VLC). FD-OOK reduces the flickering caused by a VLC transmitter and can maintain a 50% dimming level. Simple encoder and decoder are proposed which generates codes where the number of bits representing one is same as the number of bits representing zero. By keeping the number of ones and zeros equal the change in the brightness of lighting may be minimized and kept constant at 50%, thereby reducing the flickering in VLC. The performance of FD-OOK is analysed with two parameters: the spectral efficiency and power requirement.

  9. Property study of integer wavelet transform lossless compression coding based on lifting scheme

    Science.gov (United States)

    Xie, Cheng Jun; Yan, Su; Xiang, Yang

    2006-01-01

    In this paper the algorithms and its improvement of integer wavelet transform combining SPIHT and arithmetic coding in image lossless compression is mainly studied. The experimental result shows that if the order of low-pass filter vanish matrix is fixed, the improvement of compression effect is not evident when invertible integer wavelet transform is satisfied and focusing of energy property monotonic increase with transform scale. For the same wavelet bases, the order of low-pass filter vanish matrix is more important than the order of high-pass filter vanish matrix in improving the property of image compression. Integer wavelet transform lossless compression coding based on lifting scheme has no relation to the entropy of image. The effect of compression is depended on the the focuing of energy property of image transform.

  10. On Goodput and Energy Measurements of Network Coding Schemes in the Raspberry Pi

    DEFF Research Database (Denmark)

    Hernandez, Nestor; Sørensen, Chres Wiant; Cabrera, Juan

    2016-01-01

    Given that next generation networks are expected to be populated by a large number of devices, there is a need for quick deployment and evaluation of alternative mechanisms to cope with the possible generated traffic in large-scale distributed data networks. In this sense, the Raspberry Pi has been...... of state-of-the-art routing techniques. Therefore, in this work we provide an in-depth performance evaluation of Random Linear Network Coding (RLNC) based schemes for the Raspberry Pi models 1 and 2, by showing the processing speed of the encoding and decoding operations and the corresponding energy...... consumption. Our results show that, in several scenarios, processing speeds of more than 80 Mbps in the Raspberry Pi model 1 and 800 Mbps in the Raspberry Pi model 2 are attainable. Moreover, we show that the processing energy per bit for network coding is below 1 nJ or even an order of magnitude less...

  11. Efficient Data Compression Scheme using Dynamic Huffman Code Applied on Arabic Language

    Directory of Open Access Journals (Sweden)

    Sameh Ghwanmeh

    2006-01-01

    Full Text Available The development of an efficient compression scheme to process the Arabic language represents a difficult task. This paper employs the dynamic Huffman coding on data compression with variable length bit coding, on the Arabic language. Experimental tests have been performed on both Arabic and English text. A comparison was made to measure the efficiency of compressing data results on both Arabic and English text. Also a comparison was made between the compression rate and the size of the file to be compressed. It has been found that as the file size increases, the compression ratio decreases for both Arabic and English text. The experimental results show that the average message length and the efficiency of compression on Arabic text was better than the compression on English text. Also, results show that the main factor which significantly affects compression ratio and average message length was the frequency of the symbols on the text.

  12. ROCIT : a visual object recognition algorithm based on a rank-order coding scheme.

    Energy Technology Data Exchange (ETDEWEB)

    Gonzales, Antonio Ignacio; Reeves, Paul C.; Jones, John J.; Farkas, Benjamin D.

    2004-06-01

    This document describes ROCIT, a neural-inspired object recognition algorithm based on a rank-order coding scheme that uses a light-weight neuron model. ROCIT coarsely simulates a subset of the human ventral visual stream from the retina through the inferior temporal cortex. It was designed to provide an extensible baseline from which to improve the fidelity of the ventral stream model and explore the engineering potential of rank order coding with respect to object recognition. This report describes the baseline algorithm, the model's neural network architecture, the theoretical basis for the approach, and reviews the history of similar implementations. Illustrative results are used to clarify algorithm details. A formal benchmark to the 1998 FERET fafc test shows above average performance, which is encouraging. The report concludes with a brief review of potential algorithmic extensions for obtaining scale and rotational invariance.

  13. A lossless multichannel bio-signal compression based on low-complexity joint coding scheme for portable medical devices.

    Science.gov (United States)

    Kim, Dong-Sun; Kwon, Jin-San

    2014-09-18

    Research on real-time health systems have received great attention during recent years and the needs of high-quality personal multichannel medical signal compression for personal medical product applications are increasing. The international MPEG-4 audio lossless coding (ALS) standard supports a joint channel-coding scheme for improving compression performance of multichannel signals and it is very efficient compression method for multi-channel biosignals. However, the computational complexity of such a multichannel coding scheme is significantly greater than that of other lossless audio encoders. In this paper, we present a multichannel hardware encoder based on a low-complexity joint-coding technique and shared multiplier scheme for portable devices. A joint-coding decision method and a reference channel selection scheme are modified for a low-complexity joint coder. The proposed joint coding decision method determines the optimized joint-coding operation based on the relationship between the cross correlation of residual signals and the compression ratio. The reference channel selection is designed to select a channel for the entropy coding of the joint coding. The hardware encoder operates at a 40 MHz clock frequency and supports two-channel parallel encoding for the multichannel monitoring system. Experimental results show that the compression ratio increases by 0.06%, whereas the computational complexity decreases by 20.72% compared to the MPEG-4 ALS reference software encoder. In addition, the compression ratio increases by about 11.92%, compared to the single channel based bio-signal lossless data compressor.

  14. 多级网络编码方案%Multi-level network coding scheme

    Institute of Scientific and Technical Information of China (English)

    宋雪; 周异辉; 师军; 吴振强

    2015-01-01

    目前安全网络编码的研究有信息论安全和密码学安全两种方法。信息论安全的编码方案中,中继节点编码主要是使用随机线性网络编码(RLNC)生成编码矩阵,但是此方法并不能保证生成的矩阵一定满秩,从而影响方案的解码率。提出了一个多级网络编码(MLNC)方案,该方案通过在源端使用对角矩阵对消息进行编码,以降低编码复杂度;在中继节点,让入度大于等于2的节点作为编码节点,使用多级的网络编码使混淆效果更好,编码节点随机生成满秩的下三角矩阵和上三角矩阵,用它们的乘积作为编码矩阵,这样能保证编码矩阵满秩,接收节点可以成功解码。Matlab仿真结果表明,MLNC编码矩阵达到k-安全概率优于RLNC编码矩阵,并证明MLNC方案满足信息论安全。%The current secure network coding has two methods.They are information-theoretic security and cryptography security. Among the encoding methods of information-theoretic security, the encoding scheme of the relay node uses the Random Linear Network Coding(RLNC)to generate the encoding matrix. But this method does not guarantee that the resulting matrix must be full rank and affects the decoding rate. This paper proposes a Multi-Level Network Coding(MLNC) scheme. The scheme uses the triangle matrix to encode source message. On the relay node, the node whose degree is greater than or equal to 2 is used as coding node, using multi-level network coding can make the message encode mix better. The encoding nodes generate the full rank lower triangular matrix and the full rank upper triangular matrix randomly. It uses their product as an encoding matrix. This scheme will ensure encoding matrix must be full rank. The receiving node can successfully decode the data. The result of the Matlab simulation shows that the probability of the coding matrix of MLNC satisfying k-secure can be better than RLNC. And the scheme

  15. A QR code based zero-watermarking scheme for authentication of medical images in teleradiology cloud.

    Science.gov (United States)

    Seenivasagam, V; Velumani, R

    2013-01-01

    Healthcare institutions adapt cloud based archiving of medical images and patient records to share them efficiently. Controlled access to these records and authentication of images must be enforced to mitigate fraudulent activities and medical errors. This paper presents a zero-watermarking scheme implemented in the composite Contourlet Transform (CT)-Singular Value Decomposition (SVD) domain for unambiguous authentication of medical images. Further, a framework is proposed for accessing patient records based on the watermarking scheme. The patient identification details and a link to patient data encoded into a Quick Response (QR) code serves as the watermark. In the proposed scheme, the medical image is not subjected to degradations due to watermarking. Patient authentication and authorized access to patient data are realized on combining a Secret Share with the Master Share constructed from invariant features of the medical image. The Hu's invariant image moments are exploited in creating the Master Share. The proposed system is evaluated with Checkmark software and is found to be robust to both geometric and non geometric attacks.

  16. A QR Code Based Zero-Watermarking Scheme for Authentication of Medical Images in Teleradiology Cloud

    Directory of Open Access Journals (Sweden)

    V. Seenivasagam

    2013-01-01

    Full Text Available Healthcare institutions adapt cloud based archiving of medical images and patient records to share them efficiently. Controlled access to these records and authentication of images must be enforced to mitigate fraudulent activities and medical errors. This paper presents a zero-watermarking scheme implemented in the composite Contourlet Transform (CT—Singular Value Decomposition (SVD domain for unambiguous authentication of medical images. Further, a framework is proposed for accessing patient records based on the watermarking scheme. The patient identification details and a link to patient data encoded into a Quick Response (QR code serves as the watermark. In the proposed scheme, the medical image is not subjected to degradations due to watermarking. Patient authentication and authorized access to patient data are realized on combining a Secret Share with the Master Share constructed from invariant features of the medical image. The Hu’s invariant image moments are exploited in creating the Master Share. The proposed system is evaluated with Checkmark software and is found to be robust to both geometric and non geometric attacks.

  17. Coding Theorems for Cheating-Detectable Secret Sharing Schemes with Two Shares

    CERN Document Server

    Iwamoto, Mitsugu; Yamamoto, Hirosuke

    2010-01-01

    In this paper, we discuss coding theorems on a $(2, 2)$--threshold scheme in the presence of an opponent who impersonates one of the two shareholders in an asymptotic setup. We consider a situation where $n$ secrets $S^n$ from a memoryless source is blockwisely encoded to two shares and the two shares are decoded to $S^n$ with permitting negligible decoding error. We introduce correlation level of the two shares and characterize the minimum attainable rates of the shares and a uniform random number for realizing a $(2, 2)$--threshold scheme that is secure against the impersonation attack by an opponent. It is shown that, if the correlation level between the two shares equals to an $\\ell \\ge 0$, the minimum attainable rates coincide with $H(S)+\\ell$, where $H(S)$ denotes the entropy of the source, and the maximum attainable exponent of the success probability of the impersonation attack equals to $\\ell$. We also give a simple construction of an encoder and a decoder using an ordinary $(2,2)$--threshold scheme ...

  18. An Alternative Scalable Video Coding Scheme Used For Efficient Image Representation In Multimedia Applications

    Directory of Open Access Journals (Sweden)

    Aravinda T.V

    2010-07-01

    Full Text Available This paper describes a novel video coding scheme based on a three-dimensional Matching Pursuit algorithm. In addition to good compression performance at low bit rate, the proposed coder allows for flexible spatial, temporal and rate scalability thanks to its progressive coding structure. The Matching Pursuit algorithm generates a sparse composition of a video sequence in a series of spatio-temporal atoms, taken from an over complete dictionary of three-dimensional basis functions. The dictionary is generated by shifting, scaling and rotating two different mother atoms in order to cover the whole frequency cube. An embedded stream is then produced from the series of atoms. They are first distributed into sets through the set-partitioned position map algorithm (SPPM to form the index-map, inspired from bit plane encoding. Scalar quantization is then applied to the coefficients which are finally arithmetic coded. A completeMP3D codec has been implemented, and performances are shown to favorably compare to other scalable coders like MPEG-4 FGS and SPIHT-3D. In addition, the MP3D streams offer an incomparable flexibility for multiresolution streaming or adaptive decoding.

  19. A Scalable Multiple Description Scheme for 3D Video Coding Based on the Interlayer Prediction Structure

    Directory of Open Access Journals (Sweden)

    Lorenzo Favalli

    2010-01-01

    Full Text Available The most recent literature indicates multiple description coding (MDC as a promising coding approach to handle the problem of video transmission over unreliable networks with different quality and bandwidth constraints. Furthermore, following recent commercial availability of autostereoscopic 3D displays that allow 3D visual data to be viewed without the use of special headgear or glasses, it is anticipated that the applications of 3D video will increase rapidly in the near future. Moving from the concept of spatial MDC, in this paper we introduce some efficient algorithms to obtain 3D substreams that also exploit some form of scalability. These algorithms are then applied to both coded stereo sequences and to depth image-based rendering (DIBR. In these algorithms, we first generate four 3D subsequences by subsampling, and then two of these subsequences are jointly used to form each of the two descriptions. For each description, one of the original subsequences is predicted from the other one via some scalable algorithms, focusing on the inter layer prediction scheme. The proposed algorithms can be implemented as pre- and postprocessing of the standard H.264/SVC coder that remains fully compatible with any standard coder. The experimental results presented show that these algorithms provide excellent results.

  20. On Goodput and Energy Measurements of Network Coding Schemes in the Raspberry Pi

    Directory of Open Access Journals (Sweden)

    Néstor J. Hernández Marcano

    2016-10-01

    Full Text Available Given that next generation networks are expected to be populated by a large number of devices, there is a need for quick deployment and evaluation of alternative mechanisms to cope with the possible generated traffic in large-scale distributed data networks. In this sense, the Raspberry Pi has been a popular network node choice due to its reduced size, processing capabilities, low cost and its support by widely-used operating systems. For information transport, network coding is a new paradigm for fast and reliable data processing in networking and storage systems, which overcomes various limitations of state-of-the-art routing techniques. Therefore, in this work, we provide an in-depth performance evaluation of Random Linear Network Coding (RLNC-based schemes for the Raspberry Pi Models 1 and 2, by showing the processing speed of the encoding and decoding operations and the corresponding energy consumption. Our results show that, in several scenarios, processing speeds of more than 80 Mbps in the Raspberry Pi Model 1 and 800 Mbps in the Raspberry Pi Model 2 are attainable. Moreover, we show that the processing energy per bit for network coding is below 1 nJ or even an order of magnitude less in these scenarios.

  1. Integrating environmental goals into urban redevelopment schemes: lessons from the Code River, Yogyakarta, Indonesia.

    Science.gov (United States)

    Setiawan, B B

    2002-01-01

    The settlement along the bank of the Code River in Yogyakarta, Indonesia provides housing for a large mass of the city's poor. Its strategic location and the fact that most urban poor do not have access to land, attracts people to "illegally" settle along the bank of the river. This brings negative consequences for the environment, particularly the increasing domestic waste along the river and the annual flooding in the rainy season. While the public controversies regarding the existence of the settlement along the Code River were still not resolved, at the end of the 1980s, a group of architects, academics and community members proposed the idea of constructing a dike along the River as part of a broader settlement improvement program. From 1991 to 1998, thousands of local people mobilized their resources and were able to construct 6,000 metres of riverside dike along the Code River. The construction of the riverside dike along the River has become an important "stimulant" that generated not only settlement improvement, but also a better treatment of river water. As all housing units located along the River are now facing the River, the River itself is considered the "front-yard". Before the dike was constructed, the inhabitants used to treat the River as the "backyard" and therefore just throw waste into the River. They now really want to have a cleaner river, since the River is an important part of their settlement. The settlement along the Code River presents a complex range of persistent problems with informal settlements in Indonesia; such problems are related to the issues of how to provide more affordable and adequate housing for the poor, while at the same time, to improve the water quality of the river. The project represents a good case, which shows that through a mutual partnership among stakeholders, it is possible to integrate environmental goals into urban redevelopment schemes.

  2. Encryption of QR code and grayscale image in interference-based scheme with high quality retrieval and silhouette problem removal

    Science.gov (United States)

    Qin, Yi; Wang, Hongjuan; Wang, Zhipeng; Gong, Qiong; Wang, Danchen

    2016-09-01

    In optical interference-based encryption (IBE) scheme, the currently available methods have to employ the iterative algorithms in order to encrypt two images and retrieve cross-talk free decrypted images. In this paper, we shall show that this goal can be achieved via an analytical process if one of the two images is QR code. For decryption, the QR code is decrypted in the conventional architecture and the decryption has a noisy appearance. Nevertheless, the robustness of QR code against noise enables the accurate acquisition of its content from the noisy retrieval, as a result of which the primary QR code can be exactly regenerated. Thereafter, a novel optical architecture is proposed to recover the grayscale image by aid of the QR code. In addition, the proposal has totally eliminated the silhouette problem existing in the previous IBE schemes, and its effectiveness and feasibility have been demonstrated by numerical simulations.

  3. JPEG2000-Compatible Scalable Scheme for Wavelet-Based Video Coding

    Directory of Open Access Journals (Sweden)

    André Thomas

    2007-01-01

    Full Text Available We present a simple yet efficient scalable scheme for wavelet-based video coders, able to provide on-demand spatial, temporal, and SNR scalability, and fully compatible with the still-image coding standard JPEG2000. Whereas hybrid video coders must undergo significant changes in order to support scalability, our coder only requires a specific wavelet filter for temporal analysis, as well as an adapted bit allocation procedure based on models of rate-distortion curves. Our study shows that scalably encoded sequences have the same or almost the same quality than nonscalably encoded ones, without a significant increase in complexity. A full compatibility with Motion JPEG2000, which tends to be a serious candidate for the compression of high-definition video sequences, is ensured.

  4. JPEG2000-Compatible Scalable Scheme for Wavelet-Based Video Coding

    Directory of Open Access Journals (Sweden)

    Thomas André

    2007-03-01

    Full Text Available We present a simple yet efficient scalable scheme for wavelet-based video coders, able to provide on-demand spatial, temporal, and SNR scalability, and fully compatible with the still-image coding standard JPEG2000. Whereas hybrid video coders must undergo significant changes in order to support scalability, our coder only requires a specific wavelet filter for temporal analysis, as well as an adapted bit allocation procedure based on models of rate-distortion curves. Our study shows that scalably encoded sequences have the same or almost the same quality than nonscalably encoded ones, without a significant increase in complexity. A full compatibility with Motion JPEG2000, which tends to be a serious candidate for the compression of high-definition video sequences, is ensured.

  5. Efficient Multiple Description Scalable Video Coding Scheme Based on Weighted Signal Combinations

    Institute of Scientific and Technical Information of China (English)

    ZHAO Anbang; WANG Wensheng; CUI Huijuan; TANG Kun

    2007-01-01

    A simple, efficient multiple description coding (MDC) algorithm was developed based on weighted signal combinations. The scheme uses the standard video encoder with a pre-processing stage to generate multiple descriptions.The decoder then uses a post-proprocessing stage to generate multiple descriptions. The decoder then uses a post-processing algorithm to combine the descriptions to provide better image quality. A scalable codec in the MDC system allows the system to provide multiple descriptions and scalability at the same time. In addition, since the different scalable descriptions may have different qualities, a simple averaging process is not optimal. An optimal weighted combination of the two descriptions was developed based on the signal to noise ratios. Compared with the simple average combination, the algorithm significantly improved the video quality, especially with large quality differences between the two descriptions, with gains of up to 3.56 dB.

  6. Rate Distortion Analysis and Bit Allocation Scheme for Wavelet Lifting-Based Multiview Image Coding

    Science.gov (United States)

    Lasang, Pongsak; Kumwilaisak, Wuttipong

    2009-12-01

    This paper studies the distortion and the model-based bit allocation scheme of wavelet lifting-based multiview image coding. Redundancies among image views are removed by disparity-compensated wavelet lifting (DCWL). The distortion prediction of the low-pass and high-pass subbands of each image view from the DCWL process is analyzed. The derived distortion is used with different rate distortion models in the bit allocation of multiview images. Rate distortion models including power model, exponential model, and the proposed combining the power and exponential models are studied. The proposed rate distortion model exploits the accuracy of both power and exponential models in a wide range of target bit rates. Then, low-pass and high-pass subbands are compressed by SPIHT (Set Partitioning in Hierarchical Trees) with a bit allocation solution. We verify the derived distortion and the bit allocation with several sets of multiview images. The results show that the bit allocation solution based on the derived distortion and our bit allocation scheme provide closer results to those of the exhaustive search method in both allocated bits and peak-signal-to-noise ratio (PSNR). It also outperforms the uniform bit allocation and uniform bit allocation with normalized energy in the order of 1.7-2 and 0.3-1.4 dB, respectively.

  7. Semi-implicit scheme for treating radiation under M1 closure in general relativistic conservative fluid dynamics codes

    CERN Document Server

    Sdowski, Aleksander; Tchekhovskoy, Alexander; Zhu, Yucong

    2012-01-01

    A numerical scheme is described for including radiation in multi-dimensional general-relativistic conservative fluid dynamics codes. In this method, a covariant form of the M1 closure scheme is used to close the radiation moments, and the radiative source terms are treated semi-implicitly in order to handle both optically thin and optically thick regimes. The scheme has been implemented in a conservative general relativistic radiation hydrodynamics code KORAL. The robustness of the code is demonstrated on a number of test problems, including radiative relativistic shock tubes, static radiation pressure supported atmosphere, shadows, beams of light in curved spacetime, and radiative Bondi accretion. The advantages of M1 closure relative to other approaches such as Eddington closure and flux-limited diffusion are discussed, and its limitations are also highlighted.

  8. A conservative orbital advection scheme for simulations of magnetized shear flows with the PLUTO code

    Science.gov (United States)

    Mignone, A.; Flock, M.; Stute, M.; Kolb, S. M.; Muscianisi, G.

    2012-09-01

    Context. Explicit numerical computations of hypersonic or super-fast differentially rotating disks are subject to the time-step constraint imposed by the Courant condition, according to which waves cannot travel more than a fraction of a cell during a single time-step update. When the bulk orbital velocity largely exceeds any other wave speed (e.g., sound or Alfvén), as computed in the rest frame, the time step is considerably reduced and an unusually large number of steps may be necessary to complete the computation. Aims: We present a robust numerical scheme to overcome the Courant limitation by improving and extending the algorithm previously known as FARGO (fast advection in rotating gaseous objects) to the equations of magnetohydrodynamics (MHD) using a more general formalism. The proposed scheme conserves total angular momentum and energy to machine precision and works in cartesian, cylindrical, or spherical coordinates. The algorithm has been implemented in the next release of the PLUTO code for astrophysical gasdynamics and is suitable for local or global simulations of accretion or proto-planetary disk models. Methods: By decomposing the total velocity into an average azimuthal contribution and a residual term, the algorithm approaches the solution of the MHD equations through two separate steps corresponding to a linear transport operator in the direction of orbital motion and a standard nonlinear solver applied to the MHD equations written in terms of the residual velocity. Since the former step is not subject to any stability restriction, the Courant condition is computed only in terms of the residual velocity, leading to substantially larger time steps. The magnetic field is advanced in time using the constrained transport method in order to fulfill the divergence-free condition. Furthermore, conservation of total energy and angular momentum is enforced at the discrete level by properly expressing the source terms in terms of upwind Godunov fluxes

  9. FODA/IBEA satellite access scheme for MIXED traffic at variable bit and coding rates system description

    OpenAIRE

    Celandroni, Nedo; Ferro, Erina; Mihal, Vlado; Potort?, Francesco

    1992-01-01

    This report describes the FODA system working at variable coding and bit rates (FODA/IBEA-TDMA) FODA/IBEA is the natural evolution of the FODA-TDMA satellite access scheme working at 2 Mbit/s fixed rate with data 1/2 coded or uncoded. FODA-TDMA was used in the European SATINE-II experiment [8]. We remind here that the term FODA/IBEA system is comprehensive of the FODA/IBEA-TDMA (1) satellite access scheme and of the hardware prototype realised by the Marconi R.C. (U.K.). Both of them come fro...

  10. FODA/IBEA satellite access scheme for MIXED traffic at variable bit and coding rates system description

    OpenAIRE

    Celandroni, Nedo; Ferro, Erina; Mihal, Vlado; Potort?, Francesco

    1992-01-01

    This report describes the FODA system working at variable coding and bit rates (FODA/IBEA-TDMA) FODA/IBEA is the natural evolution of the FODA-TDMA satellite access scheme working at 2 Mbit/s fixed rate with data 1/2 coded or uncoded. FODA-TDMA was used in the European SATINE-II experiment [8]. We remind here that the term FODA/IBEA system is comprehensive of the FODA/IBEA-TDMA (1) satellite access scheme and of the hardware prototype realised by the Marconi R.C. (U.K.). Both of them come fro...

  11. Act No. 1183, Civil Code, 23 December 1985.

    Science.gov (United States)

    1987-01-01

    This document contains major provisions of Paraguay's 1985 Civil Code. The Code sets the marriage age at 16 for males and 14 for females and forbids marriage between natural and adopted relatives as well as between persons of the same sex. Bigamy is forbidden, as is marriage between a person and someone convicted of attempting or committing homicide against that person's spouse. Legal incompetents may not marry. Underage minors may marry with the permission of their parents or a court. Noted among the rights and duties of a married couple is the stipulation that husbands (or a judge) must give their approval before wives can legally run a business or work outside of the house or perform other specified activities. Valid marriages are dissolved only upon the death of one spouse. Remarriage in Paraguay after divorce abroad is forbidden. Spouses may legally separate after 2 years of married life (married minors must remain together until 2 years past the age of majority). Marital separation may be requested for adultery, attempted homicide by one spouse upon the other, dishonest or immoral conduct, extreme cruelty or abuse, voluntary or malicious abandonment, or the state of habitual intoxication or repeated use of drugs. Marriages can be annulled in specified cases. Marital property is subject to the community property regime, but each spouse may retain control of specified types of personal property. The Code appoints the husband as manager of community property within limits and reserves certain property to the wife. The Code permits premarital agreements about property management, and covers the dissolution and liquidation of the community property regime. The Code also sets provisions governing "de facto" unions; filiation for children born in and outside of wedlock; claims for parental recognition; kinship; and the duty to provide maintenance to spouses, children, and other relatives.

  12. A Simple Differential Modulation Scheme for Quasi-Orthogonal Space-Time Block Codes with Partial Transmit Diversity

    Directory of Open Access Journals (Sweden)

    Lingyang Song

    2007-04-01

    Full Text Available We report a simple differential modulation scheme for quasi-orthogonal space-time block codes. A new class of quasi-orthogonal coding structures that can provide partial transmit diversity is presented for various numbers of transmit antennas. Differential encoding and decoding can be simplified for differential Alamouti-like codes by grouping the signals in the transmitted matrix and decoupling the detection of data symbols, respectively. The new scheme can achieve constant amplitude of transmitted signals, and avoid signal constellation expansion; in addition it has a linear signal detector with very low complexity. Simulation results show that these partial-diversity codes can provide very useful results at low SNR for current communication systems. Extension to more than four transmit antennas is also considered.

  13. Interleaving Gains for Receive Diversity Schemes of Distributed Turbo Codes in Wireless Half–Duplex Relay Channels

    Directory of Open Access Journals (Sweden)

    Tamer H. M. Soliman

    2015-06-01

    Full Text Available This paper proposes the interleaving gain in two different distributed turbo-coding schemes: Distributed Turbo Codes (DTC and Distributed Multiple Turbo Codes (DMTC for half-duplex relay system as an extension of our previous work on turbo coding interleaver design for direct communication channel. For these schemes with half-duplex constraint, the source node transmits its information with the parity bit sequence(s to both the relay and the destination nodes during the first phase. The relay received the data from the source and process it by using decode and forward protocol. For the second transmission period, the decoded systematic data at relay is interleaved and re-encoded by a Recursive Systematic Convolutional (RSC encoder and forwarded to the destination. At destination node, the signals received from the source and relay are processed by using turbo log-MAP iterative decoding for retrieving the original information bits. We demonstrate via simulations that the interleaving gain has a large effect with DTC scheme when we use only one RSC encoder at both the source and relay with best performance when using Modified Matched S-Random (MMSR interleaver. Furthermore, by designing a Chaotic Pseudo Random Interleaver (CPRI as an outer interleaver at the source node instead of classical interleavers, our scheme can add more secure channel conditions.

  14. Two-Level Unequal Error Protection Scheme in Image Transmission System Using Multilevel Codes in Rayleigh Fading Channel

    Institute of Scientific and Technical Information of China (English)

    LI Zuo-wei; YANG Yi-xian; YUAN Dong-feng; HU Zheng-ming

    2004-01-01

    In this paper, we propose a novel Unequal Error Protection (UEP) scheme with two levels for image transmission using Multilevel Codes (MLC). By providing the best protection for the most important data, the final recovered image quality is remarkably improved both in visual effect and in Peak Signal to Noise power Ratio (PSNR) performance.

  15. Characteristics of Academic Language Register Occurring in Caretaker-Child Interaction: Development and Validation of a Coding Scheme

    Science.gov (United States)

    Aarts, Rian; Demir, Serpil; Vallen, Ton

    2011-01-01

    This article aims at validating a coding scheme designed to investigate the precursors of academic language occurring in early caretaker-child interactions. Exposure to the academic dimensions of language is an important asset for children to be successful in academic settings. The proposed analytical framework, based on systemic functional…

  16. A self-organized internal models architecture for coding sensory-motor schemes

    Directory of Open Access Journals (Sweden)

    Esaú eEscobar Juárez

    2016-04-01

    Full Text Available Cognitive robotics research draws inspiration from theories and models on cognition, as conceived by neuroscience or cognitive psychology, to investigate biologically plausible computational models in artificial agents. In this field, the theoretical framework of Grounded Cognition provides epistemological and methodological grounds for the computational modeling of cognition. It has been stressed in the literature that textit{simulation}, textit{prediction}, and textit{multi-modal integration} are key aspects of cognition and that computational architectures capable of putting them into play in a biologically plausible way are a necessity.Research in this direction has brought extensive empirical evidencesuggesting that textit{Internal Models} are suitable mechanisms forsensory-motor integration. However, current Internal Models architectures show several drawbacks, mainly due to the lack of a unified substrate allowing for a true sensory-motor integration space, enabling flexible and scalable ways to model cognition under the embodiment hypothesis constraints.We propose the Self-Organized Internal ModelsArchitecture (SOIMA, a computational cognitive architecture coded by means of a network of self-organized maps, implementing coupled internal models that allow modeling multi-modal sensory-motor schemes. Our approach addresses integrally the issues of current implementations of Internal Models.We discuss the design and features of the architecture, and provide empirical results on a humanoid robot that demonstrate the benefits and potentialities of the SOIMA concept for studying cognition in artificial agents.

  17. Network coding based joint signaling and dynamic bandwidth allocation scheme for inter optical network unit communication in passive optical networks

    Science.gov (United States)

    Wei, Pei; Gu, Rentao; Ji, Yuefeng

    2014-06-01

    As an innovative and promising technology, network coding has been introduced to passive optical networks (PON) in recent years to support inter optical network unit (ONU) communication, yet the signaling process and dynamic bandwidth allocation (DBA) in PON with network coding (NC-PON) still need further study. Thus, we propose a joint signaling and DBA scheme for efficiently supporting differentiated services of inter ONU communication in NC-PON. In the proposed joint scheme, the signaling process lays the foundation to fulfill network coding in PON, and it can not only avoid the potential threat to downstream security in previous schemes but also be suitable for the proposed hybrid dynamic bandwidth allocation (HDBA) scheme. In HDBA, a DBA cycle is divided into two sub-cycles for applying different coding, scheduling and bandwidth allocation strategies to differentiated classes of services. Besides, as network traffic load varies, the entire upstream transmission window for all REPORT messages slides accordingly, leaving the transmission time of one or two sub-cycles to overlap with the bandwidth allocation calculation time at the optical line terminal (the OLT), so that the upstream idle time can be efficiently eliminated. Performance evaluation results validate that compared with the existing two DBA algorithms deployed in NC-PON, HDBA demonstrates the best quality of service (QoS) support in terms of delay for all classes of services, especially guarantees the end-to-end delay bound of high class services. Specifically, HDBA can eliminate queuing delay and scheduling delay of high class services, reduce those of lower class services by at least 20%, and reduce the average end-to-end delay of all services over 50%. Moreover, HDBA also achieves the maximum delay fairness between coded and uncoded lower class services, and medium delay fairness for high class services.

  18. A Power Efficient Sensing/Communication Scheme: Joint Source-Channel-Network Coding by Using Compressive Sensing

    CERN Document Server

    Feizi, Soheil

    2011-01-01

    We propose a joint source-channel-network coding scheme, based on compressive sensing principles, for wireless networks with AWGN channels (that may include multiple access and broadcast), with sources exhibiting temporal and spatial dependencies. Our goal is to provide a reconstruction of sources within an allowed distortion level at each receiver. We perform joint source-channel coding at each source by randomly projecting source values to a lower dimensional space. We consider sources that satisfy the restricted eigenvalue (RE) condition as well as more general sources for which the randomness of the network allows a mapping to lower dimensional spaces. Our approach relies on using analog random linear network coding. The receiver uses compressive sensing decoders to reconstruct sources. Our key insight is the fact that, compressive sensing and analog network coding both preserve the source characteristics required for compressive sensing decoding.

  19. A MODIFIED UNEQUAL POWER ALLOCATION (UPA SCHEME FOR PERFORMANCE ENHANCEMENT IN BIT REPETITION TURBO CODES IN HIGH SPEED DOWNLINK PACKET ACCESS (HSDPA SYSTEM

    Directory of Open Access Journals (Sweden)

    B. BALAMURALITHARA

    2015-06-01

    Full Text Available In this paper, a modified optimal power allocation scheme for different bits in turbo encoder has been proposed to improve the performance of Turbo Codes system in High Speed Downlink Packet Access (HSDPA service. In a typical turbo code in HSDPA system, an encoder with code rate of 1/3 was used with bit repetition scheme or puncturing system to achieve code rate of 1/4. In this study, the author has proposed a modified unequal power allocation (UPA scheme to improve the performance of Turbo Codes in HSDPA system. The simulation and performance bound results for the proposed UPA scheme for the frame length of N = 400, code rate = 1/4 with Log-MAP decoder over Additive White Gaussian Noise (AWGN channel were obtained and compared with the typical Turbo Codes systems, which used bit repetition scheme and puncturing method without UPA. From the results, the proposed bit repetition turbo codes system with modified UPA scheme showed better performance than the typical turbo codes system without UPA using bit repetition and puncturing approaches with coding gain of 0.35 dB to 0.56 dB.

  20. A qualitative study of DRG coding practice in hospitals under the Thai Universal Coverage scheme

    National Research Council Canada - National Science Library

    Pongpirul, Krit; Walker, Damian G; Winch, Peter J; Robinson, Courtland

    2011-01-01

    ... of the diagnosis and procedure codes is crucial. However, there has been limited understandings on which health care professions are involved and how the diagnosis and procedure coding is actually done within hospital settings...

  1. 2CAuth: A New Two Factor Authentication Scheme Using QR-Code

    Directory of Open Access Journals (Sweden)

    N. Harini

    2013-04-01

    Full Text Available Password based schemes has been the standard means of authentication over decades. Enhancements use entities like ownership (something one possess, knowledge (something one knows, and inherence (something one is as first factor and mobile phones as token less second factor, in combinations, to offer different levels of security assurances, trading off usability. In this paper we present ‘2CAuth’ a new two factor authentication scheme that enhances secure usage of application information and preserves usability, without sacrificing user’s privacy. A significant feature of the scheme is that it DOES NOT call for any synchronization between Mobile Network Operator (MNO and users. The analysis of the scheme clearly brings out itseffectiveness in terms of its usability even at times of peak loads on mobile networks. The scheme has the dual advantage of carrying out the verification of transactions which involve the physical presence of the user as well as those to be done in his absence.

  2. Lifting scheme-based method for joint coding 3D stereo digital cinema with luminace correction and optimized prediction

    Science.gov (United States)

    Darazi, R.; Gouze, A.; Macq, B.

    2009-01-01

    Reproducing a natural and real scene as we see in the real world everyday is becoming more and more popular. Stereoscopic and multi-view techniques are used for this end. However due to the fact that more information are displayed requires supporting technologies such as digital compression to ensure the storage and transmission of the sequences. In this paper, a new scheme for stereo image coding is proposed. The original left and right images are jointly coded. The main idea is to optimally exploit the existing correlation between the two images. This is done by the design of an efficient transform that reduces the existing redundancy in the stereo image pair. This approach was inspired by Lifting Scheme (LS). The novelty in our work is that the prediction step is been replaced by an hybrid step that consists in disparity compensation followed by luminance correction and an optimized prediction step. The proposed scheme can be used for lossless and for lossy coding. Experimental results show improvement in terms of performance and complexity compared to recently proposed methods.

  3. The Rice coding algorithm achieves high-performance lossless and progressive image compression based on the improving of integer lifting scheme Rice coding algorithm

    Science.gov (United States)

    Jun, Xie Cheng; Su, Yan; Wei, Zhang

    2006-08-01

    In this paper, a modified algorithm was introduced to improve Rice coding algorithm and researches of image compression with the CDF (2,2) wavelet lifting scheme was made. Our experiments show that the property of the lossless image compression is much better than Huffman, Zip, lossless JPEG, RAR, and a little better than (or equal to) the famous SPIHT. The lossless compression rate is improved about 60.4%, 45%, 26.2%, 16.7%, 0.4% on average. The speed of the encoder is faster about 11.8 times than the SPIHT's and its efficiency in time can be improved by 162%. The speed of the decoder is faster about 12.3 times than that of the SPIHT's and its efficiency in time can be rasied about 148%. This algorithm, instead of largest levels wavelet transform, has high coding efficiency when the wavelet transform levels is larger than 3. For the source model of distributions similar to the Laplacian, it can improve the efficiency of coding and realize the progressive transmit coding and decoding.

  4. A Steganography Based on CT-CDMA Communication Scheme Using Complete Complementary Codes

    CERN Document Server

    Kojima, Tetsuya

    2010-01-01

    It has been shown that complete complementary codes can be applied into some communication systems like approximately synchronized CDMA systems because of its good correlation properties. CT-CDMA is one of the communication systems based on complete complementary codes. In this system, the information data of the multiple users can be transmitted by using the same set of complementary codes through a single frequency band. In this paper, we propose to apply CT-CDMA systems into a kind of steganography. It is shown that a large amount of secret data can be embedded in the stego image by the proposed method through some numerical experiments using color images.

  5. On the feedback error compensation for adaptive modulation and coding scheme

    KAUST Repository

    Choi, Seyeong

    2011-11-25

    In this paper, we consider the effect of feedback error on the performance of the joint adaptive modulation and diversity combining (AMDC) scheme which was previously studied with an assumption of perfect feedback channels. We quantify the performance of two joint AMDC schemes in the presence of feedback error, in terms of the average spectral efficiency, the average number of combined paths, and the average bit error rate. The benefit of feedback error compensation with adaptive combining is also quantified. Selected numerical examples are presented and discussed to illustrate the effectiveness of the proposed feedback error compensation strategy with adaptive combining. Copyright (c) 2011 John Wiley & Sons, Ltd.

  6. Decoding Generalized Reed-Solomon Codes and Its Application to RLCE Encryption Schemes

    OpenAIRE

    Wang, Yongge

    2017-01-01

    This paper presents a survey on generalized Reed-Solomon codes and various decoding algorithms: Berlekamp-Massey decoding algorithms; Berlekamp-Welch decoding algorithms; Euclidean decoding algorithms; discrete Fourier decoding algorithms, Chien's search algorithm, and Forney's algorithm.

  7. Improved spatio-SNR FGS video coding scheme using motion compensation on enhancement-layer

    Institute of Scientific and Technical Information of China (English)

    Jiang Tao; Zhang Zhaoyang; Ma Ran; Shi Xuli

    2006-01-01

    MPEG-4 fine-granularity-scalable (FGS) technology is an effective solution to resolve the network bandwidth varying because FGS provides very fine granular SNR scalability. However, this scalability is obtained with sacrifice of coding efficiency. An one-loop FGS structure is presented based on motion compensation (MC + FGS) to improve the coding efficiency of base FGS. Then it describes and discusses the hybrid spatial-SNR FGS (FGSS) structure that extends SNR scalability of FGS to spatial scalability (spatio-SNR scalability). FGSS structure inherent the low coding efficiency of FGS structure. Combining MC + FGS structure with FGSS structure, a structure of MC + FGSS structure is obtained which acquires both structures' advantages and counteracts both structures' defects. Experimental results prove the MC + FGSS structure not only obtains fine granular spatio-SNR scalability, but also achieves high coding efficiency.

  8. Classifying Obstructive and Nonobstructive Code Clones of Type I Using Simplified Classification Scheme: A Case Study

    Directory of Open Access Journals (Sweden)

    Miroslaw Staron

    2015-01-01

    Full Text Available Code cloning is a part of many commercial and open source development products. Multiple methods for detecting code clones have been developed and finding the clones is often used in modern quality assurance tools in industry. There is no consensus whether the detected clones are negative for the product and therefore the detected clones are often left unmanaged in the product code base. In this paper we investigate how obstructive code clones of Type I (duplicated exact code fragments are in large software systems from the perspective of the quality of the product after the release. We conduct a case study at Ericsson and three of its large products, which handle mobile data traffic. We show how to use automated analogy-based classification to decrease the classification effort required to determine whether a clone pair should be refactored or remain untouched. The automated method allows classifying 96% of Type I clones (both algorithms and data declarations leaving the remaining 4% for the manual classification. The results show that cloning is common in the studied commercial software, but that only 1% of these clones are potentially obstructive and can jeopardize the quality of the product if left unmanaged.

  9. An error resilient scheme for H.264 video coding based on distortion estimated mode decision and nearest neighbor error concealment

    Institute of Scientific and Technical Information of China (English)

    LEE Tien-hsu; WANG Jong-tzy; CHEN Jhih-bin; CHANG Pao-chi

    2006-01-01

    Although H.264 video coding standard provides several error resilience tools, the damage caused by error propagation may still be tremendous. This work is aimed at developing a robust and standard-compliant error resilient coding scheme for H.264and uses techniques of mode decision, data hiding, and error concealment to reduce the damage from error propagation. This paper proposes a system with two error resilience techniques that can improve the robustness of H.264 in noisy channels. The first technique is Nearest Neighbor motion compensated Error Concealment (NNEC) that chooses the nearest neighbors in the reference frames for error concealment. The second technique is Distortion Estimated Mode Decision (DEMD) that selects an optimal mode based on stochastically distorted frames. Observed simulation results showed that the rate-distortion performances of the proposed algorithms are better than those of the compared algorithms.

  10. A parallel 3-D discrete wavelet transform architecture using pipelined lifting scheme approach for video coding

    Science.gov (United States)

    Hegde, Ganapathi; Vaya, Pukhraj

    2013-10-01

    This article presents a parallel architecture for 3-D discrete wavelet transform (3-DDWT). The proposed design is based on the 1-D pipelined lifting scheme. The architecture is fully scalable beyond the present coherent Daubechies filter bank (9, 7). This 3-DDWT architecture has advantages such as no group of pictures restriction and reduced memory referencing. It offers low power consumption, low latency and high throughput. The computing technique is based on the concept that lifting scheme minimises the storage requirement. The application specific integrated circuit implementation of the proposed architecture is done by synthesising it using 65 nm Taiwan Semiconductor Manufacturing Company standard cell library. It offers a speed of 486 MHz with a power consumption of 2.56 mW. This architecture is suitable for real-time video compression even with large frame dimensions.

  11. Intercarrier interference reduction in MC-CDMA system through second order duobinary coded phase rotated conjugate cancellation scheme.

    Science.gov (United States)

    Chitra, S; Kumaratharan, N

    2015-01-01

    Multi-carrier code division multiple access (MC-CDMA) technique is one of the strong candidates for next generation wireless mobile communication systems. Multi-carrier systems are very much sensitive to carrier frequency offset (CFO) results in intercarrier interference (ICI). To mitigate ICI without any spectral loss, a second order duobinary coded phase rotated conjugate cancellation algorithm is proposed in this paper. In the conventional phase rotated conjugate cancellation (PRCC) technique, one path carries the MC-CDMA signal with a phase spin of ϕ and the other path carries the conjugate of the first path signal with -ϕ phase spin. This artificial phase rotation allows the transmitter to tune the transmitted signals so that the ICI effects could be mutually cancelled at the receiver. Although the PRCC technique reduces the spectral efficiency, the limitation can be overcome by the joint second order duobinary coding scheme with PRCC technique. In the proposed method, the correlative coding between the binary symbols modulated on adjacent subcarriers is used to reduce the ICI without any spectral loss. Simulation results show that the proposed PRCC method provides better carrier to interference ratio (CIR) and bit error rate (BER) performances compared to the conventional conjugate cancellation (CC) technique.

  12. Modelling of the magnetic field effects in hydrodynamic codes using a second order tensorial diffusion scheme

    Energy Technology Data Exchange (ETDEWEB)

    Breil, J; Maire, P-H; Nicolai, P; Schurtz, G [CELIA, Universite Bordeaux I, CNRS, CEA, 351 cours de la Liberation, 33405 Talence (France)], E-mail: breil@celia.u-bordeaux1.fr

    2008-05-15

    In laser produced plasmas large self-generated magnetic fields have been measured. The classical formulas by Braginskii predict that magnetic fields induce a reduction of the magnitude of the heat flux and its rotation through the Righi-Leduc effect. In this paper a second order tensorial diffusion method used to correctly solve the Righi-Leduc effect in multidimensional code is presented.

  13. Prometheus: the implementation of clinical coding schemes in French routine general practice

    Directory of Open Access Journals (Sweden)

    Laurent Letrilliart

    2006-09-01

    Conclusions Coding health problems on a routine basis proved to be feasible. However, this process can be used on a more widespread basis and linked to other management data only if physicians are specially trained and rewarded, and the software incorporates large terminologies mapped with classifications.

  14. A novel repetition space-time coding scheme for mobile FSO systems

    Science.gov (United States)

    Li, Ming; Cao, Yang; Li, Shu-ming; Yang, Shao-wen

    2015-03-01

    Considering the influence of more random atmospheric turbulence, worse pointing errors and highly dynamic link on the transmission performance of mobile multiple-input multiple-output (MIMO) free space optics (FSO) communication systems, this paper establishes a channel model for the mobile platform. Based on the combination of Alamouti space-time code and time hopping ultra-wide band (TH-UWB) communications, a novel repetition space-time coding (RSTC) method for mobile 2×2 free-space optical communications with pulse position modulation (PPM) is developed. In particular, two decoding methods of equal gain combining (EGC) maximum likelihood detection (MLD) and correlation matrix detection (CMD) are derived. When a quasi-static fading and weak turbulence channel model are considered, simulation results show that whether the channel state information (CSI) is known or not, the coding system demonstrates more significant performance of the symbol error rate (SER) than the uncoding. In other words, transmitting diversity can be achieved while conveying the information only through the time delays of the modulated signals transmitted from different antennas. CMD has almost the same effect of signal combining with maximal ratio combining (MRC). However, when the channel correlation increases, SER performance of the coding 2×2 system degrades significantly.

  15. Performance of Manchester-coded payload in an optical FSK labeling scheme

    DEFF Research Database (Denmark)

    Zhang, Jianfeng; Chi, Nan; Holm-Nielsen, Pablo Villanueva;

    2003-01-01

    The modulation crosstalk between combined frequency-shift keying (FSK) and intensity modulation (IM) in an optical label-switching network is analyzed both theoretically and experimentally. A comparison between the performance of nonreturn-to-zero (NRZ) and Manchester-coded payload is made. It is...

  16. 一种加速收敛的LDPC码译码算法%Fast Convergence Decoding Scheme for LDPC Codes

    Institute of Scientific and Technical Information of China (English)

    林志国; 马林华; 田雨; 李克志

    2011-01-01

    对高斯信道下LDPC (Low-Density Parity-Check)码的传统的译码算法进行分析,指出影响收敛速度的原因,并提出了一种基于整数运算的加速收敛的LDPC码译码算法.该算法融合分层译码(Layered Belief Propagation)算法、带偏移量的最小和算法(Offset Min-Sum)以及量化的优势.仿真验证表明该算法有效地减少了译码复杂度,加速了译码收敛,且性能上同传统的量化最小和算法相比没有下降.%We consider the convergence problem of the conventional decoding scheme of Low-Density Parity-Check (LDPC) codes over Additive White Gaussian Noise (AWGN) channels. In this correspondence, we propose a fast convergence decoding scheme based on quantization, which is a comprehensive method of taking advantage of the Layered Belief Propagation (LBP) algorithm, the Offset Min-Sum (OMS) algorithm and the quantization method. Compared to the conventional quantized Min-Sum algorithm, the proposed scheme efficiently reduces the decoding complexity and significantly accelerates the decoding convergence with no additional performance loss. We show that with simulations.

  17. 29 CFR 2530.200a-1 - Relationship of the Act and the Internal Revenue Code of 1954.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Relationship of the Act and the Internal Revenue Code of... EMPLOYEE RETIREMENT INCOME SECURITY ACT OF 1974 RULES AND REGULATIONS FOR MINIMUM STANDARDS FOR EMPLOYEE PENSION BENEFIT PLANS Scope and General Provisions § 2530.200a-1 Relationship of the Act and the...

  18. Performance analysis of ARQ schemes with code combining over Nakagami-m fading channel

    Institute of Scientific and Technical Information of China (English)

    XU Wen-bo; NIU Kai; LIN Jia-ru; HE Zhi-qiang

    2009-01-01

    This article investigates the performance of hybrid automatic repeat request (HARQ) with code combining over the ideally interleaved Nakagami-m fading channel. Two retransmission protocols with coherent equal gain code combining are adopted, where the entire frame and several selected portions of the frame are repeated in protocols Ⅰ and Ⅱ, respectively. Protocol Ⅱ could be viewed as a generalization of the recently proposed reliability-based HARQ. To facilitate performance analysis, an approximation of the product of two independent Nakagami-m distributed random variables is first developed. Then the approximate analysis is utilized to obtain exact frame error probability (FEP) for protocol Ⅰ, and the upper bound of the FEP for protocol Ⅱ. Furthermore, the throughput performance of both two protocols is presented. Simulation results show the reliability of the theoretical analysis, where protocol Ⅱ outperforms protocol Ⅰ in the throughput performance due to the reduced amount of transmitted information.

  19. A high capacity text steganography scheme based on LZW compression and color coding

    Directory of Open Access Journals (Sweden)

    Aruna Malik

    2017-02-01

    Full Text Available In this paper, capacity and security issues of text steganography have been considered by employing LZW compression technique and color coding based approach. The proposed technique uses the forward mail platform to hide the secret data. This algorithm first compresses secret data and then hides the compressed secret data into the email addresses and also in the cover message of the email. The secret data bits are embedded in the message (or cover text by making it colored using a color coding table. Experimental results show that the proposed method not only produces a high embedding capacity but also reduces computational complexity. Moreover, the security of the proposed method is significantly improved by employing stego keys. The superiority of the proposed method has been experimentally verified by comparing with recently developed existing techniques.

  20. Improved Data Transmission Scheme of Network Coding Based on Access Point Optimization in VANET

    Directory of Open Access Journals (Sweden)

    Zhe Yang

    2014-01-01

    Full Text Available VANET is a hot spot of intelligent transportation researches. For vehicle users, the file sharing and content distribution through roadside access points (AP as well as the vehicular ad hoc networks (VANET have been an important complement to that cellular network. So the AP deployment is one of the key issues to improve the communication performance of VANET. In this paper, an access point optimization method is proposed based on particle swarm optimization algorithm. The transmission performances of the routing protocol with random linear network coding before and after the access point optimization are analyzed. The simulation results show the optimization model greatly affects the VANET transmission performances based on network coding, and it can enhance the delivery rate by 25% and 14% and reduce the average delay of transmission by 38% and 33%.

  1. A Hybrid Scheme Based on Pipelining and Multitasking in Mobile Application Processors for Advanced Video Coding

    Directory of Open Access Journals (Sweden)

    Muhammad Asif

    2015-01-01

    Full Text Available One of the key requirements for mobile devices is to provide high-performance computing at lower power consumption. The processors used in these devices provide specific hardware resources to handle computationally intensive video processing and interactive graphical applications. Moreover, processors designed for low-power applications may introduce limitations on the availability and usage of resources, which present additional challenges to the system designers. Owing to the specific design of the JZ47x series of mobile application processors, a hybrid software-hardware implementation scheme for H.264/AVC encoder is proposed in this work. The proposed scheme distributes the encoding tasks among hardware and software modules. A series of optimization techniques are developed to speed up the memory access and data transferring among memories. Moreover, an efficient data reusage design is proposed for the deblock filter video processing unit to reduce the memory accesses. Furthermore, fine grained macroblock (MB level parallelism is effectively exploited and a pipelined approach is proposed for efficient utilization of hardware processing cores. Finally, based on parallelism in the proposed design, encoding tasks are distributed between two processing cores. Experiments show that the hybrid encoder is 12 times faster than a highly optimized sequential encoder due to proposed techniques.

  2. Honoring Native American Code Talkers: The Road to the Code Talkers Recognition Act of 2008 (Public Law 110-420)

    Science.gov (United States)

    Meadows, William C.

    2011-01-01

    Interest in North American Indian code talkers continues to increase. In addition to numerous works about the Navajo code talkers, several publications on other groups of Native American code talkers--including the Choctaw, Comanche, Hopi, Meskwaki, Canadian Cree--and about code talkers in general have appeared. This article chronicles recent…

  3. Application of golay complementary coded excitation schemes for non-destructive testing of sandwich structures

    Science.gov (United States)

    Arora, Vanita; Mulaveesala, Ravibabu

    2017-06-01

    In recent years, InfraRed Thermography (IRT) has become a widely accepted non-destructive testing technique to evaluate the structural integrity of composite sandwich structures due to its full-field, remote, fast and in-service inspection capabilities. This paper presents a novel infrared thermographic approach named as Golay complementary coded thermal wave imaging is presented to detect disbonds in a sandwich structure having face sheets from Glass/Carbon Fibre Reinforced (GFR/CFR) laminates and core of the wooden block.

  4. An effective coded excitation scheme based on a predistorted FM signal and an optimized digital filter

    DEFF Research Database (Denmark)

    Misaridis, Thanasis; Jensen, Jørgen Arendt

    1999-01-01

    performed with the program Field II. A commercial scanner (B-K Medical 3535) was modified and interfaced to an arbitrary function generator along with an RF power amplifier (Ritec). Hydrophone measurements in water were done to establish excitation voltage and corresponding intensity levels (I-sptp and I......This paper presents a coded excitation imaging system based on a predistorted FM excitation and a digital compression filter designed for medical ultrasonic applications, in order to preserve both axial resolution and contrast. In radars, optimal Chebyshev windows efficiently weight a nearly...

  5. Design of signal-adapted multidimensional lifting scheme for lossy coding.

    Science.gov (United States)

    Gouze, Annabelle; Antonini, Marc; Barlaud, Michel; Macq, Benoît

    2004-12-01

    This paper proposes a new method for the design of lifting filters to compute a multidimensional nonseparable wavelet transform. Our approach is stated in the general case, and is illustrated for the 2-D separable and for the quincunx images. Results are shown for the JPEG2000 database and for satellite images acquired on a quincunx sampling grid. The design of efficient quincunx filters is a difficult challenge which has already been addressed for specific cases. Our approach enables the design of less expensive filters adapted to the signal statistics to enhance the compression efficiency in a more general case. It is based on a two-step lifting scheme and joins the lifting theory with Wiener's optimization. The prediction step is designed in order to minimize the variance of the signal, and the update step is designed in order to minimize a reconstruction error. Application for lossy compression shows the performances of the method.

  6. 与Huffman码相结合的卷积码软判决译码方案%Soft Decoding Scheme of Convolution Code Combined with Huffman Coding

    Institute of Scientific and Technical Information of China (English)

    郭东亮; 陈小蔷; 吴乐南

    2002-01-01

    This paper proposes a modification of the soft output Viterbi decoding algorithm (SOVA) which combines convolution code with Huffman coding. The idea is to extract the bit probability information from the Huffman coding and use it to compute the a priori source information which can be used when the channel environment is bad. The suggested scheme does not require changes on the transmitter side. Compared with separate decoding systems, the gain in signal to noise ratio is about 0.5-1.0 dB with a limited added complexity. Simulation results show that the suggested algorithm is effective.%提出了一种与Huffman码相结合的卷积码软判决译码方案.对卷积码的软判决维特比译码算法进行了改进,由Huffman编码的码字概率计算出比特转移概率,进而得出与维特比译码的支路似然值相对应的信源先验信息,通信系统的编码端不作改动,当由于信道条件恶化等原因造成维特比译码算法的支路量度相差很小而难以进行可靠译码时,将信源先验信息作为支路量度的修正值,以改善译码的性能.与分离的信源、信道译码相比,性能增益约为0.5~1.0?dB,增加的复杂性很小.仿真实验验证了算法的有效性.

  7. Load Balancing Scheme on the Basis of Huffman Coding for P2P Information Retrieval

    Science.gov (United States)

    Kurasawa, Hisashi; Takasu, Atsuhiro; Adachi, Jun

    Although a distributed index on a distributed hash table (DHT) enables efficient document query processing in Peer-to-Peer information retrieval (P2P IR), the index costs a lot to construct and it tends to be an unfair management because of the unbalanced term frequency distribution. We devised a new distributed index, named Huffman-DHT, for P2P IR. The new index uses an algorithm similar to Huffman coding with a modification to the DHT structure based on the term distribution. In a Huffman-DHT, a frequent term is assigned to a short ID and allocated a large space in the node ID space in DHT. Throuth ID management, the Huffman-DHT balances the index registration accesses among peers and reduces load concentrations. Huffman-DHT is the first approach to adapt concepts of coding theory and term frequency distribution to load balancing. We evaluated this approach in experiments using a document collection and assessed its load balancing capabilities in P2P IR. The experimental results indicated that it is most effective when the P2P system consists of about 30, 000 nodes and contains many documents. Moreover, we proved that we can construct a Huffman-DHT easily by estimating the probability distribution of the term occurrence from a small number of sample documents.

  8. A CODING SCHEME USING GLOBAL MOTION ESTIMATION FOR AVS P-FRAME

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Block matching has been used for motion estimation and motion compensation in the Audio and Video Standard (AVS) for years. While having an acceptable performance in describing motion between frames, it requires quite a few bits to represent the motion vectors. In certain circumstances, the use of global motion estimation and compensation would perform equally well or even better than the block matching in terms of motion accuracy, while it results in the coding of global motion model parameters. In this letter, we modify an AVS coder by adding (1) six global motion model parameters to the frame header, and (2) mode selection among INTRA, SKIP, INTER-16×16,INTER-16×8, INTER-8×16, INTER-8×8, and Global Motion Compensation (GMC) modes by Lagrange optimal rate-distortion criteria. Simulation results demonstrate that over 0.1dB improvement in PSNR is obtained compared to the AVS coder for an average coded P-frame with the same bitrate.

  9. A Novel Filter Dependent CFR Scheme with Waterfilling Based Code Domain Compensation

    Science.gov (United States)

    Chang, Hyung Min; Lee, Won Cheol

    This paper proposes a novel crest factor reduction (CFR) algorithm applicable to currently deployed W-CDMA base stations. The peak-to-average ratio (PAR) reduction of the multiple carrier mixed signal, namely CFR, has been an issue in order to convey the benefit of using low-cost power amplifiers. The simple final clipping method (SFCM) as a conventional method has been widely utilized due to its simplicity and effectiveness. However, the SFCM degrades the adjacent channel leakage ratio (ACLR) characteristic as well as the signal quality indicated by either the error vector magnitude (EVM) or the peak code domain error (PCDE). Conventionally, in order to alleviate this undesired deterioration, extra channel filtering and signal quality enhancement followed by CFR might be processed in an open-loop style. Alternatively, to perform CFR by maintaining the PAR as low as possible subject to satisfying the prescribed ACLR and EVM/PCDE performance, this paper introduces the prediction filter dependent peak reduction (PFDPR) process collaboratively working with dynamic waterfilling-based code domain compensation (DWCDC). To verify the superiority of the proposed CFR algorithm, tentative simulations are conducted while maintaining the rules of legitimate W-CDMA base station test specifications.

  10. Equipment Inventory Management and Transaction Recording Using Bar Coding Scheme via VB6

    Directory of Open Access Journals (Sweden)

    Geoffrey T. Salvador, PECE

    2016-06-01

    Full Text Available The aim of the study is to implement bar coding system developed through the VB6 and Microsoft Access as mechanism for the PUP ECE Laboratory Transaction recording and monitoring. The study was concerned on proper documenting and managing the daily transaction of the ECE Laboratory with the AutoLab System.Results showed that the AutoLab System effectively automated the recording of transactions merging the existing manual method into one recording mechanism. The Automated Laboratory coined as AutoLab merged the ECE Room Utilization Log Book, ECE Borrower’s Slip and the ECE Transaction Log Book into one complete package in terms of transaction recording and equipment inventory monitoring

  11. Frequency spectrum might act as communication code between retina and visual cortex I

    Directory of Open Access Journals (Sweden)

    Xu Yang

    2015-12-01

    Full Text Available AIM: To explore changes and possible communication relationship of local potential signals recorded simultaneously from retina and visual cortex I (V1. METHODS: Fourteen C57BL/6J mice were measured with pattern electroretinogram (PERG and pattern visually evoked potential (PVEP and fast Fourier transform has been used to analyze the frequency components of those signals. RESULTS: The amplitude of PERG and PVEP was measured at about 36.7 µV and 112.5 µV respectively and the dominant frequency of PERG and PVEP, however, stay unchanged and both signals do not have second, or otherwise, harmonic generation. CONCLUSION: The results suggested that retina encodes visual information in the way of frequency spectrum and then transfers it to primary visual cortex. The primary visual cortex accepts and deciphers the input visual information coded from retina. Frequency spectrum may act as communication code between retina and V1.

  12. Oscillations, phase-of-firing coding, and spike timing-dependent plasticity: an efficient learning scheme.

    Science.gov (United States)

    Masquelier, Timothée; Hugues, Etienne; Deco, Gustavo; Thorpe, Simon J

    2009-10-28

    Recent experiments have established that information can be encoded in the spike times of neurons relative to the phase of a background oscillation in the local field potential-a phenomenon referred to as "phase-of-firing coding" (PoFC). These firing phase preferences could result from combining an oscillation in the input current with a stimulus-dependent static component that would produce the variations in preferred phase, but it remains unclear whether these phases are an epiphenomenon or really affect neuronal interactions-only then could they have a functional role. Here we show that PoFC has a major impact on downstream learning and decoding with the now well established spike timing-dependent plasticity (STDP). To be precise, we demonstrate with simulations how a single neuron equipped with STDP robustly detects a pattern of input currents automatically encoded in the phases of a subset of its afferents, and repeating at random intervals. Remarkably, learning is possible even when only a small fraction of the afferents ( approximately 10%) exhibits PoFC. The ability of STDP to detect repeating patterns had been noted before in continuous activity, but it turns out that oscillations greatly facilitate learning. A benchmark with more conventional rate-based codes demonstrates the superiority of oscillations and PoFC for both STDP-based learning and the speed of decoding: the oscillation partially formats the input spike times, so that they mainly depend on the current input currents, and can be efficiently learned by STDP and then recognized in just one oscillation cycle. This suggests a major functional role for oscillatory brain activity that has been widely reported experimentally.

  13. Turbulence Mitigation Scheme for Optical Communications using Orbital Angular Momentum Multiplexing Based on Channel Coding and Wavefront Correction

    CERN Document Server

    Zhao, Shengmei; Zhou, Li; Gong, Longyan; Cheng, Wenwen; Sheng, Yubo; Zheng, Baoyu

    2014-01-01

    The free-space optical (FSO) communication links with orbital angular momentum (OAM) multiplexing have been demonstrated that they can largely enhance the systems' capacity without a corresponding increase in spectral bandwidth, but the performance of the system is unavoidably disturbed by atmospheric turbulence (AT). Different from the existed AT disturbance, the OAM-multiplexed systems will cause both the burst and random errors for a single OAM state carrier and the `crosstalk' interference between the different OAM states carriers. In this paper, we propose a turbulence mitigation method to improve AT tolerance of OAM-multiplexed FSO communication links. In the proposed scheme, we use channel codes to correct the burst and random errors caused by AT for a single OAM state carrier; And we use wavefront correction method to correct the `crosstalk' interference between the different OAM states carriers. The improvements of AT tolerance are discussed by comparing the performance of OAM-multiplexed FSO communi...

  14. Act No. 18.802, of 23 May 1989, [amending the Civil Code and the Commercial Code and Act 16.618].

    Science.gov (United States)

    1989-01-01

    In 1989, Chile passed an Act which amended its Civil Code to change the legal status of married women. The amendments repealed the following provisions: 1) that a nondivorced married woman must keep her husband's domicile, 2) that a woman with parental authority cannot remarry unless a court appoints a guardian for the child, 3) that marital authority gives a husband legal rights over a wife's person and property, 4) that a wife need her husband's permission to enter into financial transactions or act as a guardian, 5) that a wife needs a court order or her husband's authorization to administer gifts or inheritances she received under condition that her husband not have administrative power over them, 6) that a wife's adultery results in loss of all control and profit from communal property, 7) that a wife needs her husband's permission to administer an estate or the approval of a judge to continue to administer her late husband's estate if she remarried, 8) that a married woman has diminished legal capacity, and 9) that a husband is responsible for the conduct of his wife. In addition, the Act replaced language stating that a wife owes her husband obedience and a husband owes a wife protection with language stating that each spouse owes each other respect and protection. Wives are given the unrestricted right to work, the right (shared with husbands) to discipline and educate children, the right (shared with husbands) to support after divorce regardless of fault, the right to parental authority, and the right to manage their children's property. Wives no longer have to live wherever their husbands choose. In cases of divorce, a judge will order irrevocable separation of community property and give physical custody of all minor children (boys and girls) to the wife. The position of surviving spouses in regard to inheritance is improved. Real estate brought to a marriage by a wife or received by either spouse as a gift or inheritance is no longer considered

  15. A Novel Feature Extraction Scheme with Ensemble Coding for Protein–Protein Interaction Prediction

    Directory of Open Access Journals (Sweden)

    Xiuquan Du

    2014-07-01

    Full Text Available Protein–protein interactions (PPIs play key roles in most cellular processes, such as cell metabolism, immune response, endocrine function, DNA replication, and transcription regulation. PPI prediction is one of the most challenging problems in functional genomics. Although PPI data have been increasing because of the development of high-throughput technologies and computational methods, many problems are still far from being solved. In this study, a novel predictor was designed by using the Random Forest (RF algorithm with the ensemble coding (EC method. To reduce computational time, a feature selection method (DX was adopted to rank the features and search the optimal feature combination. The DXEC method integrates many features and physicochemical/biochemical properties to predict PPIs. On the Gold Yeast dataset, the DXEC method achieves 67.2% overall precision, 80.74% recall, and 70.67% accuracy. On the Silver Yeast dataset, the DXEC method achieves 76.93% precision, 77.98% recall, and 77.27% accuracy. On the human dataset, the prediction accuracy reaches 80% for the DXEC-RF method. We extended the experiment to a bigger and more realistic dataset that maintains 50% recall on the Yeast All dataset and 80% recall on the Human All dataset. These results show that the DXEC method is suitable for performing PPI prediction. The prediction service of the DXEC-RF classifier is available at http://ailab.ahu.edu.cn:8087/ DXECPPI/index.jsp.

  16. Biometrics based key management of double random phase encoding scheme using error control codes

    Science.gov (United States)

    Saini, Nirmala; Sinha, Aloka

    2013-08-01

    In this paper, an optical security system has been proposed in which key of the double random phase encoding technique is linked to the biometrics of the user to make it user specific. The error in recognition due to the biometric variation is corrected by encoding the key using the BCH code. A user specific shuffling key is used to increase the separation between genuine and impostor Hamming distance distribution. This shuffling key is then further secured using the RSA public key encryption to enhance the security of the system. XOR operation is performed between the encoded key and the feature vector obtained from the biometrics. The RSA encoded shuffling key and the data obtained from the XOR operation are stored into a token. The main advantage of the present technique is that the key retrieval is possible only in the simultaneous presence of the token and the biometrics of the user which not only authenticates the presence of the original input but also secures the key of the system. Computational experiments showed the effectiveness of the proposed technique for key retrieval in the decryption process by using the live biometrics of the user.

  17. A New Cell-Centered Implicit Numerical Scheme for Ions in the 2-D Axisymmetric Code Hall2de

    Science.gov (United States)

    Lopez Ortega, Alejandro; Mikellides, Ioannis G.

    2014-01-01

    We present a new algorithm in the Hall2De code to simulate the ion hydrodynamics in the acceleration channel and near plume regions of Hall-effect thrusters. This implementation constitutes an upgrade of the capabilities built in the Hall2De code. The equations of mass conservation and momentum for unmagnetized ions are solved using a conservative, finite-volume, cell-centered scheme on a magnetic-field-aligned grid. Major computational savings are achieved by making use of an implicit predictor/multi-corrector algorithm for time evolution. Inaccuracies in the prediction of the motion of low-energy ions in the near plume in hydrodynamics approaches are addressed by implementing a multi-fluid algorithm that tracks ions of different energies separately. A wide range of comparisons with measurements are performed to validate the new ion algorithms. Several numerical experiments with the location and value of the anomalous collision frequency are also presented. Differences in the plasma properties in the near-plume between the single fluid and multi-fluid approaches are discussed. We complete our validation by comparing predicted erosion rates at the channel walls of the thruster with measurements. Erosion rates predicted by the plasma properties obtained from simulations replicate accurately measured rates of erosion within the uncertainty range of the sputtering models employed.

  18. Impact of the floating-point precision and interpolation scheme on the results of DNS of turbulence by pseudo-spectral codes

    CERN Document Server

    Homann, Holger; Grauer, Rainer

    2007-01-01

    In this paper we investigate the impact of the floating-point precision and interpolation scheme on the results of direct numerical simulations (DNS) of turbulence by pseudo-spectral codes. Three different types of floating-point precision configurations show no differences in the statistical results. This implies that single precision computations allow for increased Reynolds numbers due to the reduced amount of memory needed. The interpolation scheme for obtaining velocity values at particle positions has a noticeable impact on the Lagrangian acceleration statistics. A tri-cubic scheme results in a slightly broader acceleration probability density function than a tri-linear scheme. Furthermore the scaling behavior obtained by the cubic interpolation scheme exhibits a tendency towards a slightly increased degree of intermittency compared to the linear one.

  19. 面向WSN的单一和多编码方案分析%Analysis of Single and Multi-coding Scheme for Wireless Sensor Network

    Institute of Scientific and Technical Information of China (English)

    戈军; 周莲英

    2012-01-01

    This paper focuses on how to use a different encoding scheme to improve network throughput. That is, different rates/codes are studied between sensor nodes and the Network Master(NM) and between the NM and the sink. Research results show that throughput increases with the increase of the BCH coding rate. Simulation results also show that the high rate BCH code provides a higher throughput than the low rate BCH code using the single coding scheme. The multi-coding scheme is more efficient and has a very good effect on network throughput over lifetime.%研究不同速率BCH码情况下提高无线传感器网络吞吐量的方法,给出单一编码方案对网络性能的影响及网络主节点(NM)对网络寿命和吞吐量的影响.仿真结果表明,在传感器和网络主节点(NM)之问、NM和sink之间采用不同速率/编码时,网络吞吐量随BCH编码率的增加而增加,多编码方案能更高效地提高网络吞吐量.

  20. A highly reliable coding scheme for space station inventory labels%空间站物资标签高可靠性编码方案

    Institute of Scientific and Technical Information of China (English)

    许成鑫; 魏传锋; 李学东

    2014-01-01

    文章提出了一种用于空间站物资管理的RFID(Radio Frequency Identification)系统电子标签信息编码方案。在该方案中,对电子标签中存储的物资基本信息进行纠错编码,从而增强了信息的可靠性。理论分析表明,与存储更多物资基本信息的原始方案相比,在相同条件下,采用合适的纠错码,新方案的信息可靠性更高。数值仿真结果与理论分析结果相吻合。%This paper proposes an information coding scheme for electric labels in the RFID (Radio Frequency Identification) system for the inventory management in a space station. In this scheme, the electric label codes with the error control coding are made to identify the information of the inventories. The analysis results show that the information reliability of this scheme is better than that of the original scheme storing more identification information by choosing a kind of an appropriate error control coding under the same condition. The simulation results are consistent with the analysis results.

  1. Optimal modulation and coding scheme allocation of scalable video multicast over IEEE 802.16e networks

    Directory of Open Access Journals (Sweden)

    Tsai Chia-Tai

    2011-01-01

    Full Text Available Abstract With the rapid development of wireless communication technology and the rapid increase in demand for network bandwidth, IEEE 802.16e is an emerging network technique that has been deployed in many metropolises. In addition to the features of high data rate and large coverage, it also enables scalable video multicasting, which is a potentially promising application, over an IEEE 802.16e network. How to optimally assign the modulation and coding scheme (MCS of the scalable video stream for the mobile subscriber stations to improve spectral efficiency and maximize utility is a crucial task. We formulate this MCS assignment problem as an optimization problem, called the total utility maximization problem (TUMP. This article transforms the TUMP into a precedence constraint knapsack problem, which is a NP-complete problem. Then, a branch and bound method, which is based on two dominance rules and a lower bound, is presented to solve the TUMP. The simulation results show that the proposed branch and bound method can find the optimal solution efficiently.

  2. Development and validation of burnup dependent computational schemes for the analysis of assemblies with advanced lattice codes

    Science.gov (United States)

    Ramamoorthy, Karthikeyan

    The main aim of this research is the development and validation of computational schemes for advanced lattice codes. The advanced lattice code which forms the primary part of this research is "DRAGON Version4". The code has unique features like self shielding calculation with capabilities to represent distributed and mutual resonance shielding effects, leakage models with space-dependent isotropic or anisotropic streaming effect, availability of the method of characteristics (MOC), burnup calculation with reaction-detailed energy production etc. Qualified reactor physics codes are essential for the study of all existing and envisaged designs of nuclear reactors. Any new design would require a thorough analysis of all the safety parameters and burnup dependent behaviour. Any reactor physics calculation requires the estimation of neutron fluxes in various regions of the problem domain. The calculation goes through several levels before the desired solution is obtained. Each level of the lattice calculation has its own significance and any compromise at any step will lead to poor final result. The various levels include choice of nuclear data library and energy group boundaries into which the multigroup library is cast; self shielding of nuclear data depending on the heterogeneous geometry and composition; tracking of geometry, keeping error in volume and surface to an acceptable minimum; generation of regionwise and groupwise collision probabilities or MOC-related information and their subsequent normalization thereof, solution of transport equation using the previously generated groupwise information and obtaining the fluxes and reaction rates in various regions of the lattice; depletion of fuel and of other materials based on normalization with constant power or constant flux. Of the above mentioned levels, the present research will mainly focus on two aspects, namely self shielding and depletion. The behaviour of the system is determined by composition of resonant

  3. The relationship development assessment - research version: preliminary validation of a clinical tool and coding schemes to measure parent-child interaction in autism.

    Science.gov (United States)

    Larkin, Fionnuala; Guerin, Suzanne; Hobson, Jessica A; Gutstein, Steven E

    2015-04-01

    The aim of this project was to replicate and extend findings from two recent studies on parent-child relatedness in autism (Beurkens, Hobson, & Hobson, 2013; Hobson, Tarver, Beurkens, & Hobson, 2013, under review) by adapting an observational assessment and coding schemes of parent-child relatedness for the clinical context and examining their validity and reliability. The coding schemes focussed on three aspects of relatedness: joint attentional focus (Adamson, Bakeman, & Deckner, 2004), the capacity to co-regulate an interaction and the capacity to share emotional experiences. The participants were 40 children (20 with autism, 20 without autism) aged 6-14, and their parents. Parent-child dyads took part in the observational assessment and were coded on these schemes. Comparisons were made with standardised measures of autism severity (Autism Diagnostic Observation Schedule, ADOS: Lord, Rutter, DiLavore, & Risi, 2001; Social Responsiveness Scale, SRS: Constantino & Gruber, 2005), relationship quality (Parent Child Relationship Inventory, PCRI: Gerard, 1994) and quality of parent-child interaction (Dyadic Coding Scales, DCS: Humber & Moss, 2005). Inter-rater reliability was very good and, as predicted, codes both diverged from the measure of parent-child relationship and converged with a separate measure of parent-child interaction quality. A detailed profile review revealed nuanced areas of group and individual differences which may be specific to verbally-able school-age children. The results support the utility of the Relationship Development Assessment - Research Version for clinical practice. © The Author(s) 2013.

  4. SOME COMMENTS ON THE SCHEME OF ARRANGEMENT AS AN AN "AFFECTED TRANSACTION" AS DEFINED IN THE COMPANIES ACT 71 OF 2008

    Directory of Open Access Journals (Sweden)

    Stephanie M Luiz

    2012-12-01

    Full Text Available A scheme of arrangement involving a regulated company and its shareholders is defined as an "affected transaction" in the Companies Act 71 of 2008. Although scheme of arrangements, which can be used to achieve a takeover of a company, are a common occurrence, the Act provides no definition of such schemes. The importance of knowing what actually constitutes a scheme of arrangement becomes apparent when it is noted that section 121 of the Actprovides that any person making an offer which if accepted would result in an affected transaction is obliged to comply with all the relevant reporting and approval requirements in the Act, as well as the Takeover Regulations, unless the Takeover Regulation Panel has granted an exemption. Giving effect to an affected transaction is prohibited, unless the Panel has issued a compliance certificate or granted an exemption. The article comments generally on the definition of a scheme of arrangement as an affected transaction, highlighting the elements of a scheme of arrangement. Specific consideration is given to transactions which include a re-acquisition by the company of its own previously issued securities and when such a re-acquisition on its own would be considered to be a scheme of arrangement and an affected transaction. Comment on the obligation to appoint an independent expert to report on the scheme and the relevance, if any, of the solvency and liquidity of the company embarking on a scheme of arrangement is included. Finally, consideration is given to the need to have a scheme of arrangement approved by a special resolution and the potential exclusion of certain voting rights. The article exposes a number of difficulties with the interpretation of the applicable provisions and suggests that these need to be revisited by the legislature for clarification.

  5. 抗污染攻击的自适应网络编码传输机制%Adaptive secure network coding scheme against pollution attacks

    Institute of Scientific and Technical Information of China (English)

    何明; 邓罡; 王宏; 龚正虎

    2013-01-01

    The problem of pullution attacks was focused on and ASNC (adaptive secure network coding) scheme was proposed, which is an adaptive security scheme against pollution attacks in network coding systems. The proposed scheme allows participating nodes to detect polluted packets based on time and space properties of network coding. It is an innovative security scheme which can dynamically adjust the authentication strategy of participating nodes according to the security situation. In addition, ASNC scheme provides an efficient packet authentication without requiring the ex-istence of any extra secure channels. Security analysis and simulation of the scheme were also presented and the results demonstrate the practicality and efficiency of the ASNC scheme.%研究了网络编码中的污染攻击问题,提出了一种抗污染攻击的自适应网络编码传输机制ASNC (adaptive secure network coding)。在编码数据分组的传输过程中,该机制利用网络编码的时间和空间特性有效控制污染数据分组的传播。同时,ASNC机制创新性地促使网络编码系统动态调整安全策略,自适应于当前网络安全态势。此外,为了达到更好的实用性,ASNC机制有效利用网络编码的编码空间特性,不需要额外的安全数据通道和数据分组加密操作。ASNC机制的安全分析和仿真结果表明,其能够有效抵抗污染攻击,与不具有自适应能力的机制相比具有更好的安全效率。

  6. Performance Analysis of Mobile WiMAX System using Turbo Coding Technique for Different Modulation Schemes under AWGN and Rayleigh Channel

    Directory of Open Access Journals (Sweden)

    P. Samundiswary

    2013-02-01

    Full Text Available In wireless communication, future demands must be met using more data throughput wireless technologies. Since bandwidth is limited and user demand continues to grow. This problem could be solved by WiMAX technology based on IEEE 802.16e specifications, which provides high data services on mobile environment. So, to support high data rate traffic, the error correction could be enhanced by incorporating a better channel coding technique in mobile WiMAX physical layer. Further, coding technique is used for providing reliable information through the transmission channel to the user. It is used to reduce the level of noise and interferences in electronic medium. The amount of error detection and correction required and its effectiveness depends on the signal to noise ratio. The advantages of Forward Error Correction (FEC are that a back-channel is not required, or that retransmission of data can often be avoided, at the cost of higher bandwidth requirements on average. In this paper, the performance of mobile WiMAX system with convolutional turbo coding is determined and analyzed for various modulation schemes under different channels. The BER performance of mobile WiMAX system using convolutional turbo Coding is determined and compared with the existing concatenated Reed Solomon(RS coding in the presence of AWGN and Rayleigh Channel. From the simulation results, it is verified that convolutional turbo coding provides better BER performance than concatenated RS coding

  7. Dress codes and appearance policies: challenges under federal legislation, part 3: Title VII, the Americans with Disabilities Act, and the National Labor Relations Act.

    Science.gov (United States)

    Mitchell, Michael S; Koen, Clifford M; Darden, Stephen M

    2014-01-01

    As more and more individuals express themselves with tattoos and body piercings and push the envelope on what is deemed appropriate in the workplace, employers have an increased need for creation and enforcement of reasonable dress codes and appearance policies. As with any employment policy or practice, an appearance policy must be implemented and enforced without regard to an individual's race, color, sex, national origin, religion, disability, age, or any other protected status. A policy governing dress and appearance based on the business needs of an employer that is applied fairly and consistently and does not have a disproportionate effect on any protected class will generally be upheld if challenged in court. By examining some of the more common legal challenges to dress codes and how courts have resolved the disputes, health care managers can avoid many potential problems. This article, the third part of a 3-part examination of dress codes and appearance policies, focuses on the issues of race and national origin under the Civil Rights Act, disability under the Americans With Disabilities Act, and employees' rights to engage in concerted activities under the National Labor Relations Act. Pertinent court cases that provide guidance for employers are addressed.

  8. General Labour Code (Act No. 2 of 1986), 5 April 1986. [Selected provisions].

    Science.gov (United States)

    1989-01-01

    Guinea-Bissau's General Labor Code, Act No. 2 of 1986, requires that employers adopt non-discriminatory procedures in dealing with their employees, disallowing discrimination based on gender, race, national origin, religion, political ideology or inclination, or on whether or not an employee is affiliated to a worker's union. Women are guaranteed equality with men in work opportunity and employment treatment; they are assured access to any type of job, profession, or position which does not pose any potential or actual threat to their genetic functioning. Additional legislation shall establish the conditions and prohibitions for contracting woman for heavy labor, for jobs performed under insalubrious conditions, for underground work, and for other types of jobs which might endanger a woman's genetic functioning. Job offers must not discriminate, unless the restrictions or specifications are essential to the nature of the job, rendering the job qualitatively differentiable when performed by a man or a woman. The employer must ensure that female workers have the same job opportunity and treatment for professional training and career development. Different specific job categories may not be created for men and women if a woman's salary is inferior to that of a man performing equivalent work in a corresponding professional category. Protection during pregnancy and delivery guarantees a woman the right to decline medically inadvisable tasks without loss of wages; to decline overtime work; to be absent from work when necessary for maternal medical care without loss of wages; to interrupt daily work to nurse her children for 1 hour or 2 for half-hour periods for up to 1 year without the loss of wages. Every female employee has the right to 60 days pregnancy and maternity leave, without loss of wages, for whatever clinical type of delivery, including for still births and for births where the infant died shortly thereafter.

  9. Tactical data link system with low-density parity-check code scheme%采用LDPC码方案的战术数据链系统

    Institute of Scientific and Technical Information of China (English)

    李航; 陈炜

    2011-01-01

    战术数据链系统能够提高部队信息化作战能力,其中信道编码技术是保证消息传输可靠性的关键技术之一.构建了一种新的战术数据链系统,系统采用低密度奇偶校验(LDPC,Low-Density Parity-Check)码方案,LDPC码是适用于传输可靠性要求高的通信系统的新型码组.介绍了LDPC码方案中的和积算法,描述了系统的传输模型,分析了系统在固定频率和加性白色高斯噪声(AWGN,Additive White Gaussian Noise)信道条件下的链路性能.利用计算机进行蒙特卡罗仿真,结果表明:在AWGN信道和瑞利衰落信道下,LDPC编码方案可以有效地降低数据链系统的误比特率,取得比采用里德.所罗门编码的联合战术信息分发系统更好的误码性能.LDPC码作为信道编码技术的备选码组,为进一步提高战术数据链的可靠性提供了一种解决方案.%In information warfare,military combat capability can be improved by tactical data link system of which coding is one of crucial techniques of the transmission reliability.A new type of tactical data link system was proposed employing low-density parity-check(LDPC) code scheme,which is a new set of codes for communication systems demanding intensive reliability.The sum-product algorithm of the LDPC code scheme was introduced and the transmission model was described.Then the link performance of the system within the fix frequency over additive white Gaussian noise(AWGN) channel was analyzed.Simulation results with Monte-Carlo method show that the LDPC code scheme can decrease the bit error rate of the tactical data link system effectively.The results also showe that the LDPC-coded data link system achieves better performance than joint tactical information distribution system(JTIDS),which employe Reed Solomon codes as channel coding scheme,over AWGN channel and Rayleigh fading channel.LDPC codes,serving as the alternative codes for channel coding technique

  10. Secure network coding scheme of delay tolerant networks%延迟容忍网络的安全网络编码方案

    Institute of Scientific and Technical Information of China (English)

    戈军; 王志超

    2012-01-01

    Current solutions for pollution attacks require a public key infrastructure support, but this is not desirable for the mobile Ad hoc networks. Therefore, this paper proposed the network coding scheme without public key infrastructure. This scheme could better prevent such pollution attack. It allowed the packets mutual verification, and thus an intermediate node could decide whether these packets could be encoded together without authenticating the source. Analysis and comparison of other signature schemes, the results show that this network coding without public key signature function is sufficient to prevent pollution attacks.%当前针对污染攻击的解决方案需要公钥基础设施支持,但这对于移动Ad hoc网络而言并不可取,因此提出了无需公钥基础设施的网络编码方案.所提方案允许数据包相互验证,从而使中间节点可判断这些包是否可以未经源验证即可共同编码.分析和比较了其他签名方案,表明无需公钥的网络编码签名功能足以防止污染攻击.

  11. Study of cold neutron sources: Implementation and validation of a complete computation scheme for research reactor using Monte Carlo codes TRIPOLI-4.4 and McStas

    Energy Technology Data Exchange (ETDEWEB)

    Campioni, Guillaume; Mounier, Claude [Commissariat a l' Energie Atomique, CEA, 31-33, rue de la Federation, 75752 Paris cedex (France)

    2006-07-01

    The main goal of the thesis about studies of cold neutrons sources (CNS) in research reactors was to create a complete set of tools to design efficiently CNS. The work raises the problem to run accurate simulations of experimental devices inside reactor reflector valid for parametric studies. On one hand, deterministic codes have reasonable computation times but introduce problems for geometrical description. On the other hand, Monte Carlo codes give the possibility to compute on precise geometry, but need computation times so important that parametric studies are impossible. To decrease this computation time, several developments were made in the Monte Carlo code TRIPOLI-4.4. An uncoupling technique is used to isolate a study zone in the complete reactor geometry. By recording boundary conditions (incoming flux), further simulations can be launched for parametric studies with a computation time reduced by a factor 60 (case of the cold neutron source of the Orphee reactor). The short response time allows to lead parametric studies using Monte Carlo code. Moreover, using biasing methods, the flux can be recorded on the surface of neutrons guides entries (low solid angle) with a further gain of running time. Finally, the implementation of a coupling module between TRIPOLI- 4.4 and the Monte Carlo code McStas for research in condensed matter field gives the possibility to obtain fluxes after transmission through neutrons guides, thus to have the neutron flux received by samples studied by scientists of condensed matter. This set of developments, involving TRIPOLI-4.4 and McStas, represent a complete computation scheme for research reactors: from nuclear core, where neutrons are created, to the exit of neutrons guides, on samples of matter. This complete calculation scheme is tested against ILL4 measurements of flux in cold neutron guides. (authors)

  12. Act to amend the Immigration Act, 1976 and the Criminal Code in consequence thereof, 21 July 1988.

    Science.gov (United States)

    1988-01-01

    This Act is designed "1) to preserve for persons in genuine need of protection access to the procedures for determining refugee claims; 2) to control widespread abuse of the procedures for determining refugee claims, particularly in light of organized incidents involving large-scale introduction of persons into Canada to take advantage of those procedures; 3) to deter those who assist in the illegal entry of persons into Canada and thereby minimize the exploitation of and risks to persons seeking to come to Canada; and 4) to respond to security concerns, including the fulfillment of Canada's obligations in respect of internationally protected persons." The Act contains provisions that 1) increase powers of authorities to detain persons considered to be "security risks;" 2) authorize for six months the relevant minister to turn back ships if the Minister believes on "reasonable grounds" that a ship is bringing in persons in violation of immigration legislation; 3) prohibit persons from organizing, inducing, aiding, or abetting illegal immigration, or from attempting to do so; 4) prohibit transportation companies from bringing persons into Canada without first ascertaining that they have a valid visa, passport, or travel document; and 5) facilitate the seizure of vehicles and evidence. full text

  13. Random linear network coding for streams with unequally sized packets: Overhead reduction without zero-padded schemes

    DEFF Research Database (Denmark)

    Taghouti, Maroua; Roetter, Daniel Enrique Lucani; Pedersen, Morten Videbæk;

    2016-01-01

    and decoding designs, focused on processing macro-symbols (composed by a number of symbols in the appropriate finite field) instead of full zero-padded packets. Our proposed schemes provide on-the-fly decoding strategies to manage heterogeneous packet sizes without the need for fragmentation or bundling...

  14. A New Wavelength Optimization and Energy-Saving Scheme Based on Network Coding in Software-Defined WDM-PON Networks

    Science.gov (United States)

    Ren, Danping; Wu, Shanshan; Zhang, Lijing

    2016-09-01

    In view of the characteristics of the global control and flexible monitor of software-defined networks (SDN), we proposes a new optical access network architecture dedicated to Wavelength Division Multiplexing-Passive Optical Network (WDM-PON) systems based on SDN. The network coding (NC) technology is also applied into this architecture to enhance the utilization of wavelength resource and reduce the costs of light source. Simulation results show that this scheme can optimize the throughput of the WDM-PON network, greatly reduce the system time delay and energy consumption.

  15. 基于多元LDPC码的多用户协作方案%Multiuser Cooperative Scheme Based on Nonbinary LDPC Codes

    Institute of Scientific and Technical Information of China (English)

    施玉晨; 白宝明

    2013-01-01

    Compared with Turbo codes, nonbinary low-density parity-check (LDPC) codes have the better waterfall and error floor performance. The nonbinary LDPC codes are applied to decode-and-forward (DF) cooperative communications in this paper, and a multiuser cooperative scheme based on outage probability is proposed. Each user decides its relay by judging whether its channel to the source node is in outage or not. In case the channel is not in outage, the user decodes the received signal from the source node, and encodes it using nonbinary LDPC codes before forwarding to the destination. The parity-check matrix of nonbinary LDPC codes consists of information part and parity-check part. The information part is quasi-cyclic, and the parity-check part is the dual-diagonal structure. Simulation results show that, compared with the random cooperative scheme, the proposed scheme can achieve about 0.3 dB and 0.4 dB performance gains at the bit error rate (BER) of 10−4 on Gaussian channel and Rayleigh fading channel, respectively.%  与Turbo码相比,多元LDPC码有更好的waterfall和error floor性能.该文将多元LDPC码应用于译码转发协作系统中,提出基于中断概率的多用户协作方案.各用户通过判断自己与信源节点间的信道是否发生中断,决定是否作为中继.若没有发生中断,用户先对接收到的信息进行译码,再采用多元LDPC码重新编码后发送至目的节点.仿真结果表明,当误比特率(BER)为10−4时,相比于随机协作方案,该方案在高斯信道下可获得0.3 dB的性能改善,在瑞利衰落信道下可获得0.4 dB的性能改善.

  16. The South African traditional health practitioner as a beneficiary of and provider to medical funds and schemes through the traditional health practitioners Act (Act No 22, 2007: A present-day perspective

    Directory of Open Access Journals (Sweden)

    Gabriel Louw

    2017-01-01

    Full Text Available Background Payments to traditional health practitioners for services rendered from medical funds and schemes, as envisaged by the Traditional Health Practitioners Act (Act No 22, 2007, is controversial and a point of contention. Such policy was followed before in South Africa in the 1990s when some funds and schemes offered limited alternative healthcare benefits for members consulting traditional healers. Aims The study aimed to offer a contemporary view of the South African traditional health practitioner as a provider to and beneficiary of the medical funds and schemes through the Traditional Health Practitioners Act (No 22, 2007. Methods This is an exploratory and descriptive study that makes use of an historical approach by means of investigation and a literature review. The emphasis is on using current documentation like articles, books and newspapers as primary sources to reflect on the South African traditional health practitioner as a provider to and beneficiary of the medical schemes and funds through the Traditional Health Practitioners Act (No 22, 2007. The findings are offered in narrative form. Results It seems as if the South African authorities completely misunderstand the future implications of the Traditional Health Practitioners Act (No 22, 2007 on healthcare. This is specifically true when it comes to the right to claim from medical funds and schemes for services rendered by traditional health practitioners and the possible extra costs for these medical schemes and funds. Conclusion The implications of Section 42(2 of the Traditional Health Practitioners Act (No 22, 2007 which aims to set up a claiming process for traditional health practitioners, seems to be very problematic. The fact that Act No 22 (2007 has not been enacted properly nine years after its promulgation has put a halt on the professionalization of traditional healers until 2015. This also affected their status as a beneficiary of and service provider to the

  17. QR码图像预处理方案研究%Research of QR Code Image Preprocessing Scheme

    Institute of Scientific and Technical Information of China (English)

    李筱楠; 郑华; 刘会杰

    2016-01-01

    Image preprocessing is an important step in the process of QR code decoding. In this paper, a practical image preprocessing method for QR code recognition is proposed. Image binarization can reduce process computation, and locate QR code based on its symbol characteristics. Experimental results demonstrate that the proposed approach can overcome the influence from noise,inhomogeneous light and geometric distortion, and thus increase the recognition rate of the QR code.%图像预处理是QR码解码过程中的重要步骤。在传统识别方案基础上,提出一种实用的QR码图像预处理方法,对采集到的图像进行滤波和二值化处理,由位置探测图形定位 QR 码的位置和畸变角度,并通过透视变换矫正图像几何形变。实验结果表明,该方案可以克服 QR 码易受噪声干扰、光照不均和几何失真等影响的问题,显著提高了QR码的识别率。

  18. 一种基于三维小波变换的枧频图像编码方法%A Video Coding Scheme Based on Three Dimensional Wavelet

    Institute of Scientific and Technical Information of China (English)

    冯彦发; 王福龙; 余英林

    2000-01-01

    In this paper,We propose an improved zerotree coding scheme based on three dimensional wavelet transform. The wavefor coefficients are quantized with different quanttzation matrices using human visual system (HVS), and then are encoded with an improved zerotree coding algorithm. Experi-ments prove that this method is very efficient.

  19. Learning to Act Like a Lawyer: A Model Code of Professional Responsibility for Law Students

    Directory of Open Access Journals (Sweden)

    David M. Tanovich

    2009-02-01

    Full Text Available Law students are the future of the legal profession. How well prepared are they when they leave law school to assume the professional and ethical obligations that they owe themselves, the profession and the public? This question has led to a growing interest in Canada in the teaching of legal ethics. It is also led to a greater emphasis on the development of clinical and experiential learning as exemplified in the scholarship and teaching of Professor Rose Voyvodic. Less attention, however, has been placed on identifying the general ethical responsibilities of law students when not working in a clinic or other legal context. This can be seen in the presence of very few Canadian articles exploring the issue, and more significantly, in the paucity of law school discipline policies or codes of conduct that set out the professional obligations owed by law students. This article develops an idea that Professor Voyvodic and I talked about on a number of occasions. It argues that all law schools should have a code of conduct which is separate and distinct from their general University code and which resembles, with appropriate modifications, the relevant set of rules of professional responsibility law students will be bound by when called to the Bar. A student code of conduct which educates law students about their professional obligations is an important step in deterring such conduct while in law school and preparing students for ethical practice. The idea of a law school code of professional responsibility raises a number of questions. Why is it necessary for law schools to have their own student code of conduct? The article provides a threefold response. First, law students are members of the legal profession and a code of conduct should reflect this. Second, it must be relevant and comprehensive in order to ensure that it can inspire students to be ethical lawyers. And, third, as a practical matter, the last few years have witnessed a number of

  20. Design Error Performance of Space-Frequency Block Coded OFDM Systems with Different Equalizers and For Different Modulation Schemes

    Directory of Open Access Journals (Sweden)

    Rijhun Tripathi

    2012-01-01

    Full Text Available —Multiple transmit and receive antennas can be used to form multiple-input multiple-output (MIMO channels to increase the capacity (by a factor of the minimum number of transmit and receive antennas and data rate. In this paper, the combination of MIMO technology and orthogonal frequency division multiplexing (OFDM systems is considered for wideband transmission to mitigate inter symbol interference and to enhance system capacity. It owns the advantages of both MIMO and OFDM. MIMO-OFDM system exploits the space and frequency diversity simultaneously to improve the performance of system. The coding is done across OFDM subcarriers rather than OFDM symbols. In this paper, the performance of Space-Frequency (SF block coding for MIMO-OFDM along with different equalizers is investigated. Bit Error Rate (BER analysis is presented using different equalizers and then optimum equalization method is suggested.

  1. Economic Criminal Acts according to Criminal Code of Republic of Kosovo

    Directory of Open Access Journals (Sweden)

    Dr.Sc. Bajram Ukaj

    2015-06-01

    Full Text Available This article analyses the criminal offences against economy in the Criminal Code of Kosovo, which are increasingly becoming an important object of study, both at national and international levels. The criminal offences against economy are in principle blanket nature offences, guiding nature, since the vast majority of such norms are further delineated in other bylaws, while the criminal code provisions provide on criminal offences, thereby guiding towards another legal or sub-legal provision. Economic and financial crimes in Kosovo are already making a remarkable increase, as proven by statistical records of state authorities. The increased rate of economic crimes is a result of many factors and circumstances present in Kosovo, which may be different from regional countries. The inefficient fight and prevention of organized crime and corruption in the period between 1999-2010 was stimulated and favoured by several specific factors that are elaborated in this article.

  2. Quantum genetic algorithm based on multi-chain coding scheme%基于多链拓展编码方案的量子遗传算法

    Institute of Scientific and Technical Information of China (English)

    王之腾; 张宏军; 张睿; 邢英; 何健

    2012-01-01

    为了提高量子遗传算法的性能,提出了一种基于多链拓展编码方案的量子遗传算法.根据编码方案,将每个量子位分解为多个并列的基因,有效地拓展了搜索空间;结合编码方案提出量子更新策略,并引入了动态调整旋转角机制对个体进行更新,使用量子非门变异策略实现量子变异.仿真实验中,分析了使用不同变异概率[0,0.1,…,0.9,1]时对算法性能的影响,对比了分别使用普通量子遗传算法、双链编码方案、三链编码方案以及四链编码方案的量子遗传算法在优化函数极值问题时算法的性能.实验结果证明,通过增加基因链可以显著提高算法的性能,多链拓展编码方案可以提高量子遗传算法的性能,是有效的.%In order to improve the efficiency of the quantum genetic algorithm, this paper proposed a quantum genetic algorithm based on a expanded multi-chain coding scheme. The algorithm took qubit as chromosome. Each chromosome generated multiple and parallel gene chains which were mapping to multiple optimized solutions by separating qubit into multiple and parallel genes. The expanded genes chains expanded the searching space effectively and increased evolutionary rate for quantum genetic algorithm. It introduced the dynamic adjusting rotation angle mechanism to quantum rotation gate to guide individual e-volution and used quantum not-gate to prevent algorithm occurring premature convergence. The method further improved searching efficiency. In the simulation experiment, analysed the influence for the algorithm with different variation probability ( [0,0. 1 ,…,0. 9,1 ] )and used different code schemes to optimize extremal function. The simulation experiment result shows that it can obviously improve the efficiency of quantum genetic algorithm by adding gene chain, and the quantum genetic algorithm based on a expanded multi-chain coding scheme is efficient.

  3. 多源网络编码数据完整性验证方案%Data Integrity Verification Scheme for Multi-source Network Coding

    Institute of Scientific and Technical Information of China (English)

    牛淑芬; 王彩芬; 张玉磊; 曹素珍

    2015-01-01

    基于同态向量哈希函数和向量合并算法,提出一种能够抵御污染攻击的多源网络编码数据完整性验证方案。通过信源节点计算发送向量的哈希值,利用私钥对该哈希值进行签名,并将消息向量、哈希值以及哈希值的签名发送至中间节点。中间节点和信宿节点基于系统公钥,验证来自不同信源节点的线性编码消息的完整性。实验结果表明,当信源节点数大于200时,该方案的计算效率优于现有多源网络编码方案,更适用于大规模分布式网络数据的安全验证。%Taking advantage of vector merging algorithm and homomorphic Hash function,this paper proposes a data integrity scheme for multi-source network coding against pollution attacks. Each source node computes raw massage’ s Hash values and uses a secure mechanism to sign the Hash values,then appends the Hash values and its signatures to each message which sends to forward nodes and sink nodes. The forwarder can verify the integrity of network coded data from different source nodes without knowing the sources private keys and generating the Hash for the combined messages. Experimental results show that the computation efficiency of the proposed scheme is better than the existing multi-source network coding scheme,and it is more suitable for the large-scale distributed network data security verification.

  4. A premodern legacy: the "easy" criminalization of homosexual acts between women in the Finnish Penal Code of 1889.

    Science.gov (United States)

    Löfström, J

    1998-01-01

    Homosexual acts between women were criminalized in Finland in the 1889 Penal Code which also criminalized men's homosexual acts for the first time explicitly in Finnish legislation. The inclusion of women in the Penal Code took place without much ado. In the article it is argued that the uncomplicated juxtaposing of men and women was due to the legacy of a cultural pattern where man and woman, as categories, were not in an all-pervasive polarity to each other, for example, in sexual subjectivity. A cultural pattern of low gender polarization was typical of preindustrial rural culture, and it can help us apprehend also certain other features in contemporary Finnish social and political life, for example, women obtaining a general franchise and eligibility for the parliament first in the world, in 1906. A modern image of "public man" and "private woman" was only making its way in Finnish society; hence, there was not much anxiety at women's entry in politics, or, for that matter, at their potential for (homo)sexual subjectivity becoming recognized publicly in criminal law.

  5. Dress codes and appearance policies: challenges under federal legislation, part 2: title VII of the civil rights act and gender.

    Science.gov (United States)

    Mitchell, Michael S; Koen, Clifford M; Darden, Stephen M

    2014-01-01

    As more and more individuals express themselves with tattoos and body piercings and push the envelope on what is deemed appropriate in the workplace, employers have an increased need for creation and enforcement of reasonable dress codes and appearance policies. As with any employment policy or practice, an appearance policy must be implemented and enforced without regard to an individual's race, color, gender, national origin, religion, disability, age, or other protected status. A policy governing dress and appearance based on the business needs of an employer that is applied fairly and consistently and does not have a disproportionate effect on any protected class will generally be upheld if challenged in court. By examining some of the more common legal challenges to dress codes and how courts have resolved the disputes, health care managers can avoid many potential problems. This article, the second part of a 3-part examination of dress codes and appearance policies, focuses on the issue of gender under the Civil Rights Act of 1964. Pertinent court cases that provide guidance for employers are addressed.

  6. Improving quality of medical image compression using biorthogonal CDF wavelet based on lifting scheme and SPIHT coding

    Directory of Open Access Journals (Sweden)

    Beladgham Mohammed

    2011-01-01

    Full Text Available As the coming era is that of digitized medical information, an important challenge to deal with is the storage and transmission requirements of enormous data, including medical images. Compression is one of the indispensable techniques to solve this problem. In this work, we propose an algorithm for medical image compression based on a biorthogonal wavelet transform CDF 9/7 coupled with SPIHT coding algorithm, of which we applied the lifting structure to improve the drawbacks of wavelet transform. In order to enhance the compression by our algorithm, we have compared the results obtained with wavelet based filters bank. Experimental results show that the proposed algorithm is superior to traditional methods in both lossy and lossless compression for all tested images. Our algorithm provides very important PSNR and MSSIM values for MRI images.

  7. An implicit scheme for solving the anisotropic diffusion of heat and cosmic rays in the RAMSES code

    CERN Document Server

    Dubois, Yohan

    2016-01-01

    Astrophysical plasmas are subject to a tight connection between magnetic fields and the diffusion of particles, which leads to an anisotropic transport of energy. Under the fluid assumption, this effect can be reduced to an advection-diffusion equation augmenting the equations of magnetohydrodynamics. We introduce a new method for solving the anisotropic diffusion equation using an implicit finite-volume method with adaptive mesh refinement and adaptive time-stepping in the RAMSES code. We apply this numerical solver to the diffusion of cosmic ray energy, and diffusion of heat carried by electrons, which couple to the ion temperature. We test this new implementation against several numerical experiments and apply it to a simple supernova explosion with a uniform magnetic field.

  8. 基于数字签名的防污染网络编码方案%Pollution-Resistant Network Coding Scheme Based on Digital Signature

    Institute of Scientific and Technical Information of China (English)

    周赵斌; 许力

    2016-01-01

    Network coding technology has obvious advantages for improving networks throughput,balancing network load,improving bandwidth availability ratio, enhancing robustness of networks, but it can’t resist against pollution attacks directly. Recently, scholars propose the signature scheme based on homomorphic Hash function, which could better detect pollution attacks, but it is difficult to locate the contaminated node. This paper proposes a network coding scheme based on the digital signature by combining with the advantages of both. It can not only resist pollution attack, but also can effectively identify position of attack source. Thus, it reduces the impact of pollution attacks to the network and enhances the robustness of the network.%网络编码技术对于提高网络吞吐量、均衡网络负载、提高带宽利用率、增强网络的鲁棒性等方面都有明显的优势,但是无法直接抵抗污染攻击。最近,学者提出了基于同态哈希函数的签名方案,可以较好检测污染攻击,但是很难定位被污染的节点。本文结合两者的优势提出了一个基于数字签名的网络编码方案,该方案不仅能够抵抗污染攻击,而且能有效地确定出攻击源的位置,从而降低污染攻击对网络造成的影响,并提升网络的健壮性。

  9. Structural basis of the non-coding RNA RsmZ acting as a protein sponge.

    Science.gov (United States)

    Duss, Olivier; Michel, Erich; Yulikov, Maxim; Schubert, Mario; Jeschke, Gunnar; Allain, Frédéric H-T

    2014-05-29

    MicroRNA and protein sequestration by non-coding RNAs (ncRNAs) has recently generated much interest. In the bacterial Csr/Rsm system, which is considered to be the most general global post-transcriptional regulatory system responsible for bacterial virulence, ncRNAs such as CsrB or RsmZ activate translation initiation by sequestering homodimeric CsrA-type proteins from the ribosome-binding site of a subset of messenger RNAs. However, the mechanism of ncRNA-mediated protein sequestration is not understood at the molecular level. Here we show for Pseudomonas fluorescens that RsmE protein dimers assemble sequentially, specifically and cooperatively onto the ncRNA RsmZ within a narrow affinity range. This assembly yields two different native ribonucleoprotein structures. Using a powerful combination of nuclear magnetic resonance and electron paramagnetic resonance spectroscopy we elucidate these 70-kilodalton solution structures, thereby revealing the molecular mechanism of the sequestration process and how RsmE binding protects the ncRNA from RNase E degradation. Overall, our findings suggest that RsmZ is well-tuned to sequester, store and release RsmE and therefore can be viewed as an ideal protein 'sponge'.

  10. Coding for Electronic Mail

    Science.gov (United States)

    Rice, R. F.; Lee, J. J.

    1986-01-01

    Scheme for coding facsimile messages promises to reduce data transmission requirements to one-tenth current level. Coding scheme paves way for true electronic mail in which handwritten, typed, or printed messages or diagrams sent virtually instantaneously - between buildings or between continents. Scheme, called Universal System for Efficient Electronic Mail (USEEM), uses unsupervised character recognition and adaptive noiseless coding of text. Image quality of resulting delivered messages improved over messages transmitted by conventional coding. Coding scheme compatible with direct-entry electronic mail as well as facsimile reproduction. Text transmitted in this scheme automatically translated to word-processor form.

  11. Coding Schemes of Online Discussion Analysis:Categories and Application%在线讨论分析编码表的类型及应用

    Institute of Scientific and Technical Information of China (English)

    赵建华; 孔晶

    2015-01-01

    Online discussion is a critical approach for online learning. Researchers generally apply qualitative analysis methods to explore online postings, in order to conduct effective online discussion activities, to understand the meaning and character-istics of online discussion, and to know participants ’ behaviors and activities. In the past two decades, researchers have been endeav-oring to explore the impact of online discussion on participants. Various coding schemes have been developed for analyzing online discussion. The most influential coding schemes are analyzed for comparing their characteristics and values, which sheds light on adopting the qualitative analysis methods to analyze online discussion, so as to give full play to effects of online discussion on the growth of the learners.%在线讨论是开展网络学习的重要场所。为了指导有效在线讨论活动,掌握在线讨论的特点和规律,了解在线讨论参与者的活动及行为,研究者通常采用质性分析方法,对在线讨论的内容(帖子)进行分析。在过去20余年的时间里,研究者为探索在线讨论对参与者的影响做出了大量努力,提出了诸多编码表,并成为分析在线讨论的有效工具。通过对其中比较有影响的编码表及其应用价值进行深入分析,旨在为采用质性方法分析在线讨论提供可供参考的依据,以更好地发挥在线讨论促进学习者成长的影响和作用。

  12. Object recognition using coding schemes

    Science.gov (United States)

    Sadjadi, Firooz A.

    1992-12-01

    A new technique for recognizing two-dimensional objects independent of scale and orientation is presented. This technique's performance on real imagery of tactical military targets, both occluded and nonoccluded, is evaluated. The robustness of this method with respect to partial occlusion is shown. The relatively small storage requirements and fast search time make it an attractive candidate for real-time applications.

  13. Noisy Network Coding

    CERN Document Server

    Lim, Sung Hoon; Gamal, Abbas El; Chung, Sae-Young

    2010-01-01

    A noisy network coding scheme for sending multiple sources over a general noisy network is presented. For multi-source multicast networks, the scheme naturally extends both network coding over noiseless networks by Ahlswede, Cai, Li, and Yeung, and compress-forward coding for the relay channel by Cover and El Gamal to general discrete memoryless and Gaussian networks. The scheme also recovers as special cases the results on coding for wireless relay networks and deterministic networks by Avestimehr, Diggavi, and Tse, and coding for wireless erasure networks by Dana, Gowaikar, Palanki, Hassibi, and Effros. The scheme involves message repetition coding, relay signal compression, and simultaneous decoding. Unlike previous compress--forward schemes, where independent messages are sent over multiple blocks, the same message is sent multiple times using independent codebooks as in the network coding scheme for cyclic networks. Furthermore, the relays do not use Wyner--Ziv binning as in previous compress-forward sch...

  14. 基于压缩感知的语音编码新方案%New speech coding scheme based on compressed sensing

    Institute of Scientific and Technical Information of China (English)

    许佳佳

    2016-01-01

    根据语音信号的稀疏性,将压缩感知理论应用于语音信号的处理中,提出了一种语音编码的新方案。该方法在编码端采用随机高斯矩阵对语音信号进行观测,得到较少的观测值,然后使用矢量量化编码进一步压缩数据;在解码端,通过矢量量化解码得到观测值,根据语音信号在离散余弦域中的稀疏性,用正交匹配追踪算法重构语音信号。所用算法,在保证语音信号重构质量的前提下降低计算复杂度,减小时延。实验结果表明,对于采样率为44100 Hz,量化位数为16 bit,码速率为705.6 kbps单声道语音信号压缩到100 kbps左右仍具有较好的语音质量,同时算法时间延迟低。%According to the sparse of the speech signal, applied compression perception theory to speech signal processing, this paper proposes a new scheme of speech signal coding. The method using random Gaussian matrix observing the speech signal on the encoding side , obtained fewer observations,then further compress the data using vector quantization coding.In the decoder, decoding by vector quantization, getting observations based on the speech signal sparsity in the discrete cosine domain, then reconstructed speech signal using orthogonal matching pursuit algorithm . The purpose of the algorithm is to reduce the computational complexity and delay on the premise of guarantee the quality of speech signal reconstruction. Experimental results show that the mono audio signal whose sampling rate is 44100 hz, quantitative is 16 bit and bit rate is 705.6 Kbps could be compressed to around 100 Kbps, the compressed speech signal still has good voice quality, at the same time the algorithm has lower time delay.

  15. 部分信道特征下的物理层安全编码方法%Scheme of physical layer secrecy coding under partial channel characteristics

    Institute of Scientific and Technical Information of China (English)

    王亚东; 黄开枝; 吉江; 钟州

    2012-01-01

    针对部分信道特征(授权信道特征存在估计误差且窃听信道特征未知)下的物理层安全传输问题,结合人工噪声和安全编码,提出了一种实用的物理层安全编码方法.多天线发射机采用波束成型传输信号时添加与授权信道特征正交的人工噪声,利用交织LDPC码缩小安全距离,在授权信道SNR约束下求最小私密中断概率,实现功率优化分配,尽可能使窃听信道保持低SNR高BER,授权信道保持高SNR低BER,从而实现物理层安全传输.仿真结果表明,在授权信道SNR约束下,本方法可以实现较低的私密中断概率.%This paper proposed a scheme of physical layer secrecy coding under partial channel characteristics aiming at physical layer secure transmission problem. The multi-antenna transmitter exploited beam-former to send signal with artificial noise which was orthogonal with authorized channel characteristics. It used interleaving LDPC to reduce the security gap between authorized channel and eavesdropping channel. Then found the minimum secrecy outage probability with authorized channel SNR constraint, and archived the optimal power allocation for physical layer secure transmission. So the authorized channel could keep low BER with high SNR, while the eavesdropping channel could only have high BER with low SNR. Simulation results show that, the proposed method can realize lower secrecy outage probability with authorized channel SNR constraint.

  16. [Dynamics of functional parameters in different schemes for bronchial asthma therapy: results of the STRELA-ACT multicentre study].

    Science.gov (United States)

    Ogorodova, L M; Kulikov, E S; Deev, I A; Cherniak, B A; Fassakhov, R S

    2011-01-01

    Different strategies for disease control in real clinical practice are compared in terms of dynamics of functional parameters in patients with persistent bronchial asthma. This prospective multicentre surveillance study was carried out in 19 Russian clinics using the common protocol. The patients were divided in 3 groups in accordance with the changes of basal antiinflammatory therapy during the study period. Group A--stepwise increase in the extent of combined salmoterol/fluticason therapy, group B--long-term stable-dose salmoterol/fluticason therapy, group C--salmoterol/fluticason therapy with gradual decrease of the dose and/or transition to an alternative variant. Statistical analysis using Statistica 6.0 program included data from 543 patients. The results suggest that the two first modalities increased the level of control (ACT test) and improved characteristics of external respiration throughout the study period. Strategy 3 was associated with a decrease in the external respiration function and the level of control.

  17. New code match strategy for wideband code division multiple access code tree management

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Orthogonal variable spreading factor channelization codes are widely used to provide variable data rates for supporting different bandwidth requirements in wideband code division multiple access (WCDMA) systems. A new code match scheme for WCDMA code tree management was proposed. The code match scheme is similar to the existing crowed-first scheme. When choosing a code for a user, the code match scheme only compares the one up layer of the allocated codes, unlike the crowed-first scheme which perhaps compares all up layers. So the operation of code match scheme is simple, and the average time delay is decreased by 5.1%. The simulation results also show that the code match strategy can decrease the average code blocking probability by 8.4%.

  18. A lossless data coding and hiding scheme for fingerprint templates%针对指纹模板的可逆信息隐藏编码方法

    Institute of Scientific and Technical Information of China (English)

    胡校成; 张卫明; 俞能海

    2011-01-01

    通过融合指纹、人脸、口令等用户身份信息来进行多模态认证可以提高身份认证系统的安全性.而利用信息隐藏技术,可以将几种身份信息嵌入到某一种生物模板中实现安全存储.本文介绍了一种以指纹模板为隐藏栽体的多模态认证技术,该技术的关键问题是要保证嵌入信息后的指纹图片的质量,以确保匹配的精度.为此,提出了一种将二元信息稀疏化的数据嵌入编码方法,利用这种编码可以有效降低数据嵌入过程中对指纹图片的修改,从而改善载密图片的质量,以达到提高匹配精度的目的.该方法嵌入脆弱水印,用于指纹模板的完整性认证.%By merging several kinds of user authentication information such as fingerprints, faces, passwords etc. , multi-modal authentication can improve the security of traditional identify authentication systems. Furthermore, via data hiding technology, specific user identities can be imbedded into their biologic templates to ensure safe storage A multi-modal authentication scheme was introduced, which uses fingerprint templates as the cover. The key problem of this technology is to ensure the quality of the template picture after embedding, which is important for the matching precision afterwards. Both theoretical analysis and experimental results demonstrate that by adopting a coding method which increases the sparseness of the original binary data before embedding, modification of the fingerprint template is lowers effectively, thus ensuring the image quality and matching precision. The method embeds fragile watermarks for the integrity authentication of the fingerprint template.

  19. Biodiesel Fuel Company Owner Pleads Guilty to Fraud and Clean Air Act Crimes Connected to Renewable Fuels Scheme / Philip J. Rivkin faces more than 10 years imprisonment and $51 million in restitution

    Science.gov (United States)

    WASHINGTON - Philip Joseph Rivkin, a.k.a. Felipe Poitan Arriaga, 50, today pleaded guilty to a Clean Air Act false statement and mail fraud as part of his role in a scheme to defraud EPA by falsely representing that he was producing millions of gall

  20. Product Codes for Optical Communication

    DEFF Research Database (Denmark)

    Andersen, Jakob Dahl

    2002-01-01

    Many optical communicaton systems might benefit from forward-error-correction. We present a hard-decision decoding algorithm for the "Block Turbo Codes", suitable for optical communication, which makes this coding-scheme an alternative to Reed-Solomon codes.......Many optical communicaton systems might benefit from forward-error-correction. We present a hard-decision decoding algorithm for the "Block Turbo Codes", suitable for optical communication, which makes this coding-scheme an alternative to Reed-Solomon codes....

  1. New QC-LDPC codes based Niederreiter cryptography scheme by using dual public-key%基于QC-LD PC码的双公钥 Niederreiter密码方案

    Institute of Scientific and Technical Information of China (English)

    李冲; 韩益亮

    2016-01-01

    As an important research ofpost-quantum cryptography,code-based cryptography had excellent characteristics of low complexity and high security.With the code-based cryptosystem as the core knowledge,we constructed a new QC-LDPC codes based Niederreiter cryptography scheme by using dual public-key.And the safety analysis shows that the new scheme not only resists the common method of attack,but also meets the IND-CCA2 security.The analysis of performance of the scheme is also given.We can get the conclusions that public key sizes reduce by 63%and the information rate increase by 47%.%基于编码的公钥密码体制作为抗量子攻击密码理论的重要研究内容,具有加/解密复杂性低和安全性高的优异特性。针对Niederreiter公钥密码体制进行了研究,利用QC-LDPC码和双公钥的相关知识构造了一种新的Niederreiter加密方案。安全性分析表明,加密方案能抵抗常见攻击方法的同时满足随机预言机模型下的IND-CCA2安全。最后对方案的性能进行分析,较原有Niederreiter密码的公钥量减少63%和信息率提高47%的结论。

  2. Two-level information management scheme based on visual cryptography and QR code%基于视觉密码和QR码的两级信息管理方案

    Institute of Scientific and Technical Information of China (English)

    刘莺迎; 付正欣; 王益伟

    2016-01-01

    设计了一种新的扩展多秘密视觉密码,能够分享n个公开信息和n-1个隐私信息,其像素扩展度为4且相对差为1/4。在此基础上,结合QR码提出了一种两级信息管理方案,其中一般参与者的共享份可以呈现参与者公开信息的QR码,而且管理者的共享份与一般共享份叠加后,可以呈现参与者隐私信息的QR码。实验结果表明,公开信息和隐私信息的QR码尽管存在失真,仍可以被正确识别。%This paper designed a new extended multi-secret visual cryptography scheme (EMVCS),which could share n pub-lic information and n-1 private information.The pixel expansion of EMVCS was 4,and the relative difference was 1/4.Fur-thermore,it proposed a new two-level information management scheme based on EMVCS and QR code,in which the common participants’shares could display public information QR code.Meanwhile,the private information QR code of common partici-pants would be shown by stacking the share of manager and common participant.The experimental results demonstrate that the distorted QR codes of public and private information can be recognized correctly.

  3. An Improved Scheme of QR Code Based on Visual Crypotography%基于可视密码的改进 QR 码方案

    Institute of Scientific and Technical Information of China (English)

    张舒; 李凌

    2015-01-01

    QR码在二维码技术中最具代表性,目前广泛应用于电子票务领域。论文针对QR码无法保证用户个人信息的安全问题,利用可视密码技术,采用基于异或(XOR)运算的(2,2)可视密码方案,易于操作且提高了 QR 码的安全性与可靠性。%QR code is widely used in Electronic ticketing which belongs to one of the two‐dimensional code .In order to solve the security issues of protected information of QR Code ,visual cryptography technology is introduced .A (2 ,2) VCS with XOR algorithm what used in this paper is simple to decrypt and the safety and reliability of QR Code has been im‐proved .

  4. A Novel Diversity-Multiplexing Tradeoff Scheme in Cooperative MIMO Based on Distributed Space-Time Coding%一种基于分布式空时码的协作MIMO分集复用折衷新方案

    Institute of Scientific and Technical Information of China (English)

    许晓荣; 章坚武; 郑宝玉

    2011-01-01

    Cooperative MIMO which is composed of multiple single antenna nodes by cooperative communication could construct multipte virtual transmit antennas. Spatial diversity gain could be obtained from this virtual MIMO multiple antenna arrays. Considered the specific features of cooperative MIMO, code cooperation strategy with distributed space-time coding is implemented in the network. An enhanced divemity-multiplexing tradeoff (DMT) scheme based on distributed space-time ceding (DSTC) in cooperative MIMO is studied. The expression of outage probability and diversity gain of two DSTC strategies are derived in detail. Based on the two DMT schemes of DSTC, the optimal DMT and outage performance of the enhanced DMT strategy could be obtained through altering the threshold of multiplexing gain adaptively. Numerical results indicate that, the proposed DMT scheme could be asymptotical to DMT upper bound in cooperative MIMO, and the corresponding outage performance is also inferior to that of upper bound. Hence, cooperative diversity gain and optimum outage behavior could be achieved simultaneously by the proposed DMT scheme for DSTC code cooperation in multi-node cooperative MIMO scenario.%协作MIMO通过多个单天线节点的相互协作构造多发射天线,以此形成一种虚拟MIMO多天线阵列获得空间分集增益.考虑到协作MIMO特点,天线间采用分布式空时编码进行编码协作.文章研究了协作MIMO中基于分布式空时码(DSTC)的分集复用折衷(DMT)新方案,该方案通过推导两种DSTC的中断概率与分集增益表达式,结合两类DSYC的DMT策略,根据改变复用增益阈值自适应获得最佳DMT与中断性能.数值仿真表明,所提的DMT策略可以逼近协作MIMO的DMT上限,协作节点采用该策略的中断性能仅次于上限的中断性能.在多节点构成协作MIMO网络分布式空时编码协作中,提出的DMT新方案可使系统高效地获得协作分集增益与中断性能.

  5. Quantum Superdense Coding Scheme Based on High-dimensional Two-particles System%基于高维两粒子纠缠态的超密编码方案

    Institute of Scientific and Technical Information of China (English)

    黄平武; 周萍; 农亮勤; 何良明; 尹彩流

    2011-01-01

    基于通信双方预先共享d维二粒子最大纠缠态非定域相关性,信息发送方Bob只需要向信息接收者Alice传送一个粒子,就可以传送log22比特经典信息,为保护信息的安全,方案采用诱骗光子技术,安全性等价于改进后的原始量子密钥分配方案(Bennett-Brassard 1984,BB84).本文讨论了基于高维纯纠缠态超密编码方案.即通过引入一个附加量子比特,信息接收方对手中的纠缠粒子和附加粒子在执行相应的幺正演化,可以获取d|ak|2 logd2 +logd2(ak=min{aj},j ∈ {O,L,d-1})比特经典信息.通信双方采用诱骗光子技术确保量子信道的安全建立.与其他方案相比,该方案具有通信效率较高、实用性较强的优点.%The author presents a generalized superdense coding scheme based on high-dimensional two particles maximally entangled state following some ideas of superdense coding scheme based on fourdimensional two particles. The quantum superdense coding based on noisy quantum channel was discussed. The receiver(Alice)can extract d|αk|2 logdj2 + log2d (αk = min {α}, j ∈ {0,L,d-1 } ) bits classic information by introducing one auxiliary two-level particle and perfprming corresponding unitray operation on her particles. All the parties can use some decoy photons to set up their quantum channel securely. The scheme only requires pure entangled state, which makes this scheme more convenient than others in practical application. Moreover, it has the advantage of having high communication efficiency.

  6. Hybrid Noncoherent Network Coding

    CERN Document Server

    Skachek, Vitaly; Nedic, Angelia

    2011-01-01

    We describe a novel extension of subspace codes for noncoherent networks, suitable for use when the network is viewed as a communication system that introduces both dimension and symbol errors. We show that when symbol erasures occur in a significantly large number of different basis vectors transmitted through the network and when the min-cut of the networks is much smaller then the length of the transmitted codewords, the new family of codes outperforms their subspace code counterparts. For the proposed coding scheme, termed hybrid network coding, we derive two upper bounds on the size of the codes. These bounds represent a variation of the Singleton and of the sphere-packing bound. We show that a simple concatenated scheme that represents a combination of subspace codes and Reed-Solomon codes is asymptotically optimal with respect to the Singleton bound. Finally, we describe two efficient decoding algorithms for concatenated subspace codes that in certain cases have smaller complexity than subspace decoder...

  7. Dress codes and appearance policies: challenges under federal legislation, part 1: title VII of the civil rights act and religion.

    Science.gov (United States)

    Mitchell, Michael S; Koen, Clifford M; Moore, Thomas W

    2013-01-01

    As more and more individuals choose to express themselves and their religious beliefs with headwear, jewelry, dress, tattoos, and body piercings and push the envelope on what is deemed appropriate in the workplace, employers have an increased need for creation and enforcement of reasonable dress codes and appearance policies. As with any employment policy or practice, an appearance policy must be implemented and enforced without regard to an individual's race, color, sex, national origin, religion, disability, age, or any other protected status. A policy governing dress and appearance based on the business needs of an employer that is applied fairly and consistently and does not have a disproportionate effect on any protected class will generally be upheld if challenged in court. By examining some of the more common legal challenges to dress codes and how courts have resolved the disputes, health care managers can avoid many potential problems. This article addresses the issue of religious discrimination focusing on dress and appearance and some of the court cases that provide guidance for employers.

  8. 在网格中重用遗留代码的一种实现方案%A scheme for reusing of legacy code in grid

    Institute of Scientific and Technical Information of China (English)

    苟和平; 冯百明; 邹燕飞; 景永霞

    2007-01-01

    针对遗留代码的共享需求提出了在网格中重用LC(Legacy Code)的M-W(Migration-Wrapping)方法.该方法把LC变换为XML格式,迁移到Web服务器之后,包装、部署成Web服务以供访问者调用.采用M-W方法,只需付出低廉的代价就可实现大量LC在新系统中的重新利用.

  9. Turbo Codes Extended with Outer BCH Code

    DEFF Research Database (Denmark)

    Andersen, Jakob Dahl

    1996-01-01

    The "error floor" observed in several simulations with the turbo codes is verified by calculation of an upper bound to the bit error rate for the ensemble of all interleavers. Also an easy way to calculate the weight enumerator used in this bound is presented. An extended coding scheme is proposed...

  10. A Secure Signature Scheme for Wireless Body Area Networks Based on Network Coding and ECC Algorithm%基于网络编码和ECC的无线体域网安全签名方案

    Institute of Scientific and Technical Information of China (English)

    蒙云番; 孙光昊; 邢杰; 万海斌; 覃团发

    2015-01-01

    Security challenges in wireless body area networks ( WBAN) have been paid unprecedented at-tention for the vulnerable of patient’s personal sensitive data. In order to address prevalent security con-cerns,a secure signature scheme based on network coding and elliptic curve cryptography( ECC) algorithm is proposed. The scheme firstly introduces network coding to establish a multicast model in WBAN. The en-ergy efficiency of the network increases as more volume of data will be transmitted to the sink with the same number of transmissions. Through signing the packets by utilizing ECC algorithm,secure communication of patient-related physiological data is possible in hostile environments. The scheme includes three phases,i. e. ,setup,signature and verification. Data simulation proves that the scheme is secure,simultaneously pro-vides authentication and detects malicious nodes that intentionally corrupt content on the network.%针对无线体域网( WBAN)应用中人们关注的病患个人敏感数据在传输过程中容易受到攻击的安全问题,提出一种结合随机网络编码和椭圆曲线密码学( ECC)的安全签名方案。该方案首先在网络中引入随机网络编码建立多播网络模型,增加相同传输次数下的数据信息量;通过采用ECC算法对信息进行签名,保障病患相关生理信息的通信安全。该方案共有三个阶段,即创建、签名和验证阶段。理论证明了该方案是安全的,能够有效地对信息进行污染验证,并确定受攻击节点的位置。

  11. Capacity-achieving CPM schemes

    CERN Document Server

    Perotti, Alberto; Benedetto, Sergio; Montorsi, Guido

    2008-01-01

    The pragmatic approach to coded continuous-phase modulation (CPM) is proposed as a capacity-achieving low-complexity alternative to the serially-concatenated CPM (SC-CPM) coding scheme. In this paper, we first perform a selection of the best spectrally-efficient CPM modulations to be embedded into SC-CPM schemes. Then, we consider the pragmatic capacity (a.k.a. BICM capacity) of CPM modulations and optimize it through a careful design of the mapping between input bits and CPM waveforms. The so obtained schemes are cascaded with an outer serially-concatenated convolutional code to form a pragmatic coded-modulation system. The resulting schemes exhibit performance very close to the CPM capacity without requiring iterations between the outer decoder and the CPM demodulator. As a result, the receiver exhibits reduced complexity and increased flexibility due to the separation of the demodulation and decoding functions.

  12. Sliding Window-based Network Coding Transmission Scheme for Vehicular Ad hoc Networks%车载自组网中基于滑动窗口的网络编码传输策略

    Institute of Scientific and Technical Information of China (English)

    王万良; 李桂森; 姚信威; 岑跃峰

    2012-01-01

    Time-sensitive data transmission in vehicular Ad hoc networks (VANET) is particularly challenging due to the high mobility and the rapidly changing topology. To address this problem, we proposed a scheme that uses network coding with dynamic sliding window in opportunistic routing. By adjusting the window size according to the network status, it encodes different number of native packets into a coded packet such that it can tolerate the acknowledgement delay and improve the throughput in different cases. The scheme uses a lower triangular matrix coding method to smooth the decoding interval in the receiver. Simulations show that the scheme is able to increase the throughput and decrease the delay jitter efficiently. It is especially appropriate for time sensitive multimedia applications in VANET.%由于节点的高速移动和拓扑的快速变化,使得在车载自组网中传输时延敏感的数据是一个很大的挑战.针对此问题,提出了一种在机会路由上使用基于滑动窗口的网络编码传输策略.该策略根据网络状态自适应地调整滑动窗口的大小,来编码不同长度的编码包,去容忍ACK的延迟,使得在各种网络条件下都能保持较高的吞吐率;使用下三角形式的渐进编码使接收端逐步解码,从而平滑接收端的解码时间间隔.仿真结果表明,该策略具有更高的吞吐率,同时能够在接收端形成时延抖动小的数据流,为车载自组网中流媒体等时延敏感的数据流传输提供更好的服务质量.

  13. Act No. 42/1988 instituting the Preliminary Title and First Book of the Civil Code, 27 October 1988.

    Science.gov (United States)

    1988-01-01

    This document contains major provisions of the Preliminary Title and First Book (dealing with persons and the family) of the Civil Code enacted by Rwanda in 1988. These include the portions of Part 1 (physical persons) which deal with personality, birth, identification of physical persons, legal names, residence and domicile, and proof of civil status. Included sections of Part 2 (the family) cover marriage, engagement, the conclusion of marriage (with sections devoted to general provisions, substantive conditions, obligations arising from marriage, and respective rights and duties of spouses), the annulment of marriages and the effects of an annulled marriage, the dissolution of marriage and separation (divorce for specific reasons, divorce by mutual consent, and the effects of divorce), kinship and filiation (the kinship of children born legitimately or in marriage; proof of legitimate filiation; and legitimization, recognition, and support of natural children), adoption, and parental authority (general provisions, the right of custody, legal administration, legal enjoyment, loss of parental authority). The only section of Part 3 contained herein relates to the duty of the customary family council.

  14. A dominant nuclear mutation in Chlamydomonas identifies a factor controlling chloroplast mRNA stability by acting on the coding region of the atpA transcript.

    Science.gov (United States)

    Drapier, Dominique; Girard-Bascou, Jacqueline; Stern, David B; Wollman, Francis-André

    2002-09-01

    We have characterized a nuclear mutation, mda1-ncc1, that affects mRNA stability for the atpA gene cluster in the chloroplast of Chlamydomonas. Unlike all nuclear mutations altering chloroplast gene expression described to date, mda1-ncc1 is a dominant mutation that still allows accumulation of detectable amounts of atpA mRNAs. At variance with the subset of these mutations that affect mRNA stability through the 5' UTR of a single chloroplast transcript, the mutated version of MDA1 acts on the coding region of the atpA message. We discuss the action of MDA1 in relation to the unusual pattern of expression of atpA that associates particularly short lived-transcripts with a very high translational efficiency.

  15. Examples of numerical simulations of two-dimensional unsaturated flow with VS2DI code using different interblock conductivity averaging schemes

    Directory of Open Access Journals (Sweden)

    Szymkiewicz Adam

    2015-09-01

    Full Text Available Flow in unsaturated porous media is commonly described by the Richards equation. This equation is strongly nonlinear due to interrelationships between water pressure head (negative in unsaturated conditions, water content and hydraulic conductivity. The accuracy of numerical solution of the Richards equation often depends on the method used to estimate average hydraulic conductivity between neighbouring nodes or cells of the numerical grid. The present paper discusses application of the computer simulation code VS2DI to three test problems concerning infiltration into an initially dry medium, using various methods for inter-cell conductivity calculation (arithmetic mean, geometric mean and upstream weighting. It is shown that the influence of the averaging method can be very large for coarse grid, but that it diminishes as cell size decreases. Overall, the arithmetic average produced the most reliable results for coarse grids. Moreover, the difference between results obtained with various methods is a convenient indicator of the adequacy of grid refinement.

  16. Examples of numerical simulations of two-dimensional unsaturated flow with VS2DI code using different interblock conductivity averaging schemes

    Science.gov (United States)

    Szymkiewicz, Adam; Tisler, Witold; Burzyński, Kazimierz

    2015-09-01

    Flow in unsaturated porous media is commonly described by the Richards equation. This equation is strongly nonlinear due to interrelationships between water pressure head (negative in unsaturated conditions), water content and hydraulic conductivity. The accuracy of numerical solution of the Richards equation often depends on the method used to estimate average hydraulic conductivity between neighbouring nodes or cells of the numerical grid. The present paper discusses application of the computer simulation code VS2DI to three test problems concerning infiltration into an initially dry medium, using various methods for inter-cell conductivity calculation (arithmetic mean, geometric mean and upstream weighting). It is shown that the influence of the averaging method can be very large for coarse grid, but that it diminishes as cell size decreases. Overall, the arithmetic average produced the most reliable results for coarse grids. Moreover, the difference between results obtained with various methods is a convenient indicator of the adequacy of grid refinement.

  17. CSR schemes in agribusiness

    DEFF Research Database (Denmark)

    Pötz, Katharina Anna; Haas, Rainer; Balzarova, Michaela

    2013-01-01

    Purpose – The rise of CSR followed a demand for CSR standards and guidelines. In a sector already characterized by a large number of standards, the authors seek to ask what CSR schemes apply to agribusiness, and how they can be systematically compared and analysed. Design....../methodology/approach – Following a deductive-inductive approach the authors develop a model to compare and analyse CSR schemes based on existing studies and on coding qualitative data on 216 CSR schemes. Findings – The authors confirm that CSR standards and guidelines have entered agribusiness and identify a complex landscape...... of schemes that can be categorized on focus areas, scales, mechanisms, origins, types and commitment levels. Research limitations/implications – The findings contribute to conceptual and empirical research on existing models to compare and analyse CSR standards. Sampling technique and depth of analysis limit...

  18. Combining image-processing and image compression schemes

    Science.gov (United States)

    Greenspan, H.; Lee, M.-C.

    1995-01-01

    An investigation into the combining of image-processing schemes, specifically an image enhancement scheme, with existing compression schemes is discussed. Results are presented on the pyramid coding scheme, the subband coding scheme, and progressive transmission. Encouraging results are demonstrated for the combination of image enhancement and pyramid image coding schemes, especially at low bit rates. Adding the enhancement scheme to progressive image transmission allows enhanced visual perception at low resolutions. In addition, further progressing of the transmitted images, such as edge detection schemes, can gain from the added image resolution via the enhancement.

  19. 基于人眼视觉特性的低比特率图像压缩编码%Improved iow bit-rate image coding scheme based on human visual system.

    Institute of Scientific and Technical Information of China (English)

    王力; 王向阳

    2011-01-01

    为了提高编码速度和改进视觉效果,提出了一种改进的低比特率SPIHT算法.算法首先用提升小波对原始图像进行分解,再结合人眼视觉掩蔽特性,对不同区域内图像信息所对应的小波系数赋予不同视觉权值,以保证优先传输视觉上的最重要系数,最后根据系数重要性,对低频系数采用新的排列结构,并采用SPIHT编码思想完成图像压缩.实验结果表明,该算法压缩效果优于SPIHT图像压缩方案,特别在低比特率下.%A improved low bit-rate image coding scheme is presented. The lifting wavelet transform is applied to the original image,and the visual gains are achieved by exploiting Human Visual System(HVS) characteristics to weigh wavelet coefficients according to their perceptual importance. Lastly, the lower frequency exploits a new partitioning structure based on the importance of coefficients.The experimental results showthat the modified image compression scheme provides higher perceptual quality and higher PSNR than SPIHT,especially at low bit rates.

  20. 基于时分同步码多址的无线数据传输方案%Wireless data transmission scheme based on time division-synchronous code division multiple access

    Institute of Scientific and Technical Information of China (English)

    雷文君; 张会业; 崔燕

    2012-01-01

    为了在嵌入式系统中整合无线通信技术进行数据传输,提出一种基于嵌入式的无线数据传输设备的设计方案。无线数据传输设备以三星的S3C2440为中央处理器,时分同步码多址(TD-SCDMA)模块LC6311为网络接入部分。实际测试结果表明,设计方案可确保无线数据的远程传输,实时性好,运行可靠,既能提高网络传输质量,还能降低频谱监测中的隐患,故可应用于频谱远程监控领域。%To integrate wireless communication technique for data transmission in embedded system,an embedded based designing scheme for wireless data transmission is proposed.The wireless data transmission device uses the S3C2440 of Samsung as its central processing unit and time division-synchronous code division multiple access module LC6311 as the part of network access.The testing result indicates that the design of the scheme can ensure long-distance transmission of wireless data,and has got good real-time performance and reliable operation.It not only improves the quality of network transmission,but also greatly reduces the hidden dangers of Spectrum Monitoring,thus the scheme can be applied in the long-distance of spectrum monitoring.

  1. DVB-S2中基于RM码的ACM模式帧同步设计%Design of Frame Synchronization in ACM Scheme of DVB-S2 with RM Code

    Institute of Scientific and Technical Information of China (English)

    闫朝星; 王华; 匡镜明; 韩术

    2011-01-01

    设计和分析了DVB-S2系统中自适应编码调制(ACM)模式下基于里德-穆勒(Reed-Muller,RM)码的帧同步技术.从最大似然角度分析了一阶RM码基于快速哈达玛变换(FHT)的译码算法.采用差分相关技术检测帧头,提出一种降低误帧率的RM码译码实现方法,将帧头段的偶数位数据共轭叠加到奇数位信号上再译码.仿真结果表明,这种方法的译码性能不受任何大小相位偏差的影响,且实现复杂度较小.%The algorithm analysis of frame synchronization techniques with RM code were given for the adaptive coding and modulation (ACM) scheme in next generation satellite digital video broadcasting (DVB-S2). Based on maximum likelihood criterion, the principle of decoding RM code by fast Hadamard transformation (FHT) was analyzed. As the differential correlation detection method was employed to detect the location of frame header, a method to improve the frame error rate performance of RM decoding was presented. After combining the odd header symbols with the conjunction of even frame header symbols, the decoding performance will be robust to any phase offsets with low implementation complexity.

  2. Progressive encoding with non-linear source codes for compression of low-entropy sources

    OpenAIRE

    Ramírez Javega, Francisco; Lamarca Orozco, M. Meritxell; García Frías, Javier

    2010-01-01

    We propose a novel scheme for source coding of non-uniform memoryless binary sources based on progressively encoding the input sequence with non-linear encoders. At each stage, a number of source bits is perfectly recovered, and these bits are thus not encoded in the next stage. The last stage consists of an LDPC code acting as a source encoder over the bits that have not been recovered in the previous stages. Peer Reviewed

  3. The miR-223 host non-coding transcript linc-223 induces IRF4 expression in acute myeloid leukemia by acting as a competing endogenous RNA

    KAUST Repository

    Mangiavacchi, Arianna

    2016-08-10

    Alterations in genetic programs required for terminal myeloid differentiation and aberrant proliferation characterize acute myeloid leukemia (AML) cells. Here, we identify the host transcript of miR-223, linc-223, as a novel functional long non-coding RNA (lncRNA) in AML. We show that from the primary nuclear transcript, the alternative production of miR-223 and linc-223 is finely regulated during monocytic differentiation. Moreover, linc-223 expression inhibits cell cycle progression and promotes monocytic differentiation of AML cells. We also demonstrate that endogenous linc-223 localizes in the cytoplasm and acts as a competing endogenous RNA for miR-125-5p, an oncogenic microRNA in leukemia. In particular, we show that linc-223 directly binds to miR-125-5p and that its knockdown increases the repressing activity of miR-125-5p resulting in the downregulation of its target interferon regulatory factor 4 (IRF4), which it was previously shown to inhibit the oncogenic activity of miR-125-5p in vivo. Furthermore, data from primary AML samples show significant downregulation of linc-223 in different AML subtypes. Therein, these findings indicate that the newly identified lncRNA linc-223 may have an important role in myeloid differentiation and leukemogenesis, at least in part, by cross-talking with IRF4 mRNA.

  4. A New Achievability Scheme for the Relay Channel

    CERN Document Server

    Kang, Wei

    2007-01-01

    In this paper, we propose a new coding scheme for the general relay channel. This coding scheme is in the form of a block Markov code. The transmitter uses a superposition Markov code. The relay compresses the received signal and maps the compressed version of the received signal into a codeword conditioned on the codeword of the previous block. The receiver performs joint decoding after it has received all of the B blocks. We show that this coding scheme can be viewed as a generalization of the well-known Compress-And-Forward (CAF) scheme proposed by Cover and El Gamal. Our coding scheme provides options for preserving the correlation between the channel inputs of the transmitter and the relay, which is not possible in the CAF scheme. Thus, our proposed scheme may potentially yield a larger achievable rate than the CAF scheme.

  5. Colour schemes

    DEFF Research Database (Denmark)

    van Leeuwen, Theo

    2013-01-01

    This chapter presents a framework for analysing colour schemes based on a parametric approach that includes not only hue, value and saturation, but also purity, transparency, luminosity, luminescence, lustre, modulation and differentiation....

  6. Multiple LDPC decoding for distributed source coding and video coding

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Luong, Huynh Van; Huang, Xin

    2011-01-01

    Distributed source coding (DSC) is a coding paradigm for systems which fully or partly exploit the source statistics at the decoder to reduce the computational burden at the encoder. Distributed video coding (DVC) is one example. This paper considers the use of Low Density Parity Check Accumulate...... (LDPCA) codes in a DSC scheme with feed-back. To improve the LDPC coding performance in the context of DSC and DVC, while retaining short encoder blocks, this paper proposes multiple parallel LDPC decoding. The proposed scheme passes soft information between decoders to enhance performance. Experimental...

  7. Coded Schemes for Asymmetric Wireless Interfaces

    DEFF Research Database (Denmark)

    Moreira, André; Roetter, Daniel Enrique Lucani

    2015-01-01

    system with full duplex interfaces. Our second goal is to understand the practical implications of these results by designing a protocol for file transmissions, implement it in Android smart phones, and measure its performance when combining various interfaces, including, Bluetooth, WiFi, and 3G cellular...

  8. Sistema de otto-codificação modificado para endereçamento de redes hidrográficas An improved stream network addressing system: the modified pfafstetter coding scheme

    Directory of Open Access Journals (Sweden)

    Natanael dos Santos Silva

    2008-10-01

    .This paper presents a new numbering system based on the Pfafstetter codification scheme developed for stream networks. Its main advantage is the use of the segments' length instead of the catchments' areas for establishing the Pfafstetter code, therefore eliminating the need for elevation data. This methodology was then implemented in a software named Otto-Sys, developed for Arc/INFO workstation in AML. In order to present the results of this new approach, a case study was carried out for the stream network of the Caeté River, a tributary of Iaco River, belonging to the Amazon River basin. The details of such a digital hydrographic dataset led to 5 level-deep codes. Each codification level is stored as a new column of the attribute table and the corresponding level dictates the number of digits of the code. Once this codification scheme has been established, network-tracing tasks can be performed in any geographic information system using only attribute queries. This strategy speeds up such processes enabling them to be extended to real-time web-based devices.

  9. 一种基于量子超密编码的代理盲签名方案的研究%Research on a Proxy Blind Signature Scheme Based on Quantum Superdense Coding

    Institute of Scientific and Technical Information of China (English)

    王辉; 石润华; 仲红; 汪开婷

    2016-01-01

    Proxy blind signature is widely applied to electronic voting, electronic commerce, and other network settings, etc. Combined with the situation of electronic bank payment, considering the correlative factors of the communication cost, the quantum operation complexity, and the veriifcation efficiency, etc, the paper proposes a proxy blind signature scheme based on the single particle superdense coding to blind the classical double bits information. The principle of the scheme is that the classical bit information is transmitted to the quantum system using the measurement of single particle in different measurement bases, in which the owner of the message blinds the secret message first and then the proxy signer signs the blinded message after authorized. Under the situation of without considering the particles detection, compared with other current well-known schemes, the biggest advantage of the scheme is to save half of the particles at least. In addition, signature party only needs to measure single particle and the length of the signature is appropriate.The verification party only needs to verify by contrast, and not needs to carry out the particle operation. The efifciencies of the signature ,veriifcation and communication are all improved.%代理盲签名在电子投票系统、电子商务系统和网络环境等方面有着广泛的应用。文章结合当下电子银行支付的情况,综合考虑现实情形下的通信开销、量子操作复杂性、验证效率等相关因素,首次提出一种基于单粒子超密编码来盲化经典双比特信息的量子代理盲签名方案。该方案原理是利用单粒子在不同测量基下的测量,将经典比特信息传送到量子系统中。消息拥有者先将秘密盲化,代理签名者在经过授权后对盲化消息进行有效签名。与现今其他主流方案相比,该方案最大的优势是使用的量子资源大大减少,在不考虑检测粒子的情形下,至少节

  10. Orthogonal coding of object location.

    Science.gov (United States)

    Knutsen, Per Magne; Ahissar, Ehud

    2009-02-01

    It has been argued whether internal representations are encoded using a universal ('the neural code') or multiple codes. Here, we review a series of experiments that demonstrate that tactile encoding of object location via whisking employs an orthogonal, triple-code scheme. Rats, and other rodents, actively move the whiskers back and forth to localize and identify objects. Neural recordings from primary sensory afferents, along with behavioral observations, demonstrate that vertical coordinates of contacted objects are encoded by the identity of activated afferents, horizontal coordinates by the timing of activation and radial coordinates by the intensity of activation. Because these codes are mutually independent, the three-dimensional location of an object could, in principle, be encoded by individual afferents during single whisker-object contacts. One advantage of such a same-neuron-different-codes scheme over the traditionally assumed same-code-different-neurons scheme is a reduction of code ambiguity that, in turn, simplifies decoding circuits.

  11. Neural coding using telegraphic switching of magnetic tunnel junction

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Dong Ik; Bae, Gi Yoon; Oh, Heong Sik; Park, Wanjun, E-mail: wanjun@hanyang.ac.kr [Department of Electronic Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2015-05-07

    In this work, we present a synaptic transmission representing neural coding with spike trains by using a magnetic tunnel junction (MTJ). Telegraphic switching generates an artificial neural signal with both the applied magnetic field and the spin-transfer torque that act as conflicting inputs for modulating the number of spikes in spike trains. The spiking probability is observed to be weighted with modulation between 27.6% and 99.8% by varying the amplitude of the voltage input or the external magnetic field. With a combination of the reverse coding scheme and the synaptic characteristic of MTJ, an artificial function for the synaptic transmission is achieved.

  12. LDGM Codes for Channel Coding and Joint Source-Channel Coding of Correlated Sources

    Directory of Open Access Journals (Sweden)

    Javier Garcia-Frias

    2005-05-01

    Full Text Available We propose a coding scheme based on the use of systematic linear codes with low-density generator matrix (LDGM codes for channel coding and joint source-channel coding of multiterminal correlated binary sources. In both cases, the structures of the LDGM encoder and decoder are shown, and a concatenated scheme aimed at reducing the error floor is proposed. Several decoding possibilities are investigated, compared, and evaluated. For different types of noisy channels and correlation models, the resulting performance is very close to the theoretical limits.

  13. 基于压缩感知的低速率语音编码新方案%New low bit rate speech coding scheme based on compressed sensing

    Institute of Scientific and Technical Information of China (English)

    叶蕾; 杨震; 孙林慧

    2011-01-01

    利用语音小波高频系数的稀疏性和压缩感知原理,提出一种新的基于压缩感知的低速率语音编码方案,其中小波高频系数的压缩感知重构分别采用l1范数优化方案及码本预测方案进行,前者对大幅度样值重构效果较好,且不仅适用于语音,也适用于音乐信号,具有传统的线性预测编码方法无法比拟的优势,后者对稀疏系数位置的估计较好,且不需要采用压缩感知重构常用的基追踪算法或匹配追踪算法,从而减少了计算量.两种方法的联合使用能发挥各自的优势,使得重构语音的音质进一步改善.%Utilizing the sparsity of high frequency wavelet transform coefficients of speech signal and theory of compressed sensing, a new low bit rate speech coding scheme based on compressed sensing is proposed. The reconstruction of high frequency wavelet transform coefficients is achieved by l1 normal optimization and codebook prediction reconstruction respectively. L1 reconstruction has good effect for large coefficients and suits for both speech and music, with which traditional linear prediction coding cannot compare. Codebook prediction reconstruction has good effect for the location of sparse coefficients and reduces the amount of calculation due to not using basis pursuit or matching pursuit. The combination of these two reconstruction methods can bring the advantages of both methods and improve the quality of the reconstructed speech.

  14. Non-Pauli observables for CWS codes

    Science.gov (United States)

    Santiago, Douglas F. G.; Portugal, Renato; Melo, Nolmar

    2013-05-01

    It is known that nonadditive quantum codes can have higher code dimensions than stabilizer codes for the same length and minimum distance. The class of codeword stabilized codes (CWS) provides tools to obtain new nonadditive quantum codes by reducing the problem to finding nonlinear classical codes. In this work, we establish some results on the kind of non-Pauli operators that can be used as observables in the decoding scheme of CWS codes and propose a procedure to obtain those observables.

  15. 一种基于NSCT和图像融合的多视点图像编码方法%A Multi-view Image Coding Scheme Based on NSCT and Image Fusion

    Institute of Scientific and Technical Information of China (English)

    孙季丰; 倪秀敏

    2011-01-01

    提出了一种基于相邻视点图像融合的多视点图像编码方法.该方法首先将多幅同一场景的多视点视频图像进行融合,得到一幅含有大部分信息的融合图像、边信息和视差矢量.之后对融合图像作基于NSCT的类SPIHT编,对边信息和视差矢量进行熵编码.该编码方案,通过图像融合,有效降低了多视点视频图像传输和存储过程中的信息量.解码后的图像视觉质量和实验结果表明,该方法能更有效地表示图像的边缘信息,获得比传统编码方法更高的峰值信噪比,具有实践意义.%A multi-view image coding scheme is proposed. Different sources of images are fused in to one image, and then the fusion results are encoded. The encoder utilizes the set partitioning in hierarchical trees (SPIHT) algorithm which is suitably modified to take into account the new hierarchical structure of NSCT coefficients and the correlation between them. This approach is so efficient that it provides comparable performance to JPEG2000 objectively and subjectively. The superior result of encoder, confirms the potential of this approach.

  16. A Novel MBAFF Scheme of AVS

    Institute of Scientific and Technical Information of China (English)

    Jian-Wen Chen; Guo-Ping Li; Yun He

    2006-01-01

    Adaptive frame/field coding techniques have been adopted in many international video standards for interlaced sequence coding. When the frame/field adaptation is applied on the picture level, the coding efficiency is improved greatly,compared with the pure frame coding or the pure field coding. The picture-level adaptive frame/field coding (PAFF) selects frame coding or field coding once for one picture. If this frame/field adaptation is extended to Macro Block (MB) level, the coding efficiency will be further increased. In this paper, a novel MB-level adaptive frame/field (MBAFF) coding scheme is proposed. In the proposed MBAFF scheme, the top field of the current picture is used as a reference. The experiments are implemented on the platforms of Audio Video coding Standard (AVS) base profile and H.264/AVC, respectively. On the AVS platform, 0.35dB gain can be achieved averagely, compared with AVS1.0 anchor. On the H.264/AVC platform, 0.16dB gain can be achieved averagely, compared with MBAFF scheme of H.264/AVC. Additionally, an extensive subjective quality enhancement can be achieved by the proposed scheme.

  17. On the Concatenation of Non-Binary Random Linear Fountain Codes with Maximum Distance Separable Codes

    CERN Document Server

    Blasco, Francisco Lazaro

    2011-01-01

    A novel fountain coding scheme has been introduced. The scheme consists of a parallel concatenation of a MDS block code with a LRFC code, both constructed over the same field, $F_q$. The performance of the concatenated fountain coding scheme has been analyzed through derivation of tight bounds on the probability of decoding failure as a function of the overhead. It has been shown how the concatenated scheme performs as well as LRFC codes in channels characterized by high erasure probabilities, whereas they provide failure probabilities lower by several orders of magnitude at moderate/low erasure probabilities.

  18. Homomorphic encryption from codes

    CERN Document Server

    Bogdanov, Andrej

    2011-01-01

    We propose a new homomorphic encryption scheme based on the hardness of decoding under independent random noise from certain affine families of codes. Unlike in previous lattice-based homomorphic encryption schemes, where the message is hidden in the noisy part of the ciphertext, our scheme carries the message in the affine part of the transformation and applies noise only to achieve security. Our scheme can tolerate noise of arbitrary magnitude, as long as the noise vector has sufficiently small hamming weight (and its entries are independent). Our design achieves "proto-homomorphic" properties in an elementary manner: message addition and multiplication are emulated by pointwise addition and multiplication of the ciphertext vectors. Moreover, the extremely simple nature of our decryption makes the scheme easily amenable to bootstrapping. However, some complications are caused by the inherent presence of noticeable encryption error. Our main technical contribution is the development of two new techniques for...

  19. Fountain Codes with Multiplicatively Repeated Non-Binary LDPC Codes

    CERN Document Server

    Kasai, Kenta

    2010-01-01

    We study fountain codes transmitted over the binary-input symmetric-output channel. For channels with small capacity, receivers needs to collects many channel outputs to recover information bits. Since a collected channel output yields a check node in the decoding Tanner graph, the channel with small capacity leads to large decoding complexity. In this paper, we introduce a novel fountain coding scheme with non-binary LDPC codes. The decoding complexity of the proposed fountain code does not depend on the channel. Numerical experiments show that the proposed codes exhibit better performance than conventional fountain codes, especially for small number of information bits.

  20. Joint Source, Channel Coding, and Secrecy

    Directory of Open Access Journals (Sweden)

    Magli Enrico

    2007-01-01

    Full Text Available We introduce the concept of joint source coding, channel coding, and secrecy. In particular, we propose two practical joint schemes: the first one is based on error-correcting randomized arithmetic codes, while the second one employs turbo codes with compression, error protection, and securization capabilities. We provide simulation results on ideal binary data showing that the proposed schemes achieve satisfactory performance; they also eliminate the need for external compression and ciphering blocks with a significant potential computational advantage.

  1. Joint Source, Channel Coding, and Secrecy

    Directory of Open Access Journals (Sweden)

    Enrico Magli

    2007-09-01

    Full Text Available We introduce the concept of joint source coding, channel coding, and secrecy. In particular, we propose two practical joint schemes: the first one is based on error-correcting randomized arithmetic codes, while the second one employs turbo codes with compression, error protection, and securization capabilities. We provide simulation results on ideal binary data showing that the proposed schemes achieve satisfactory performance; they also eliminate the need for external compression and ciphering blocks with a significant potential computational advantage.

  2. Research of DCI Coding Scheme and Digital Certificates in Digital Copyright Protection%数字版权保护中DCI编码方案及数字证书研究

    Institute of Scientific and Technical Information of China (English)

    杨树林; 孙丽; 胡洁萍

    2012-01-01

    Digital copyright identifier provides a unique identity for digital content on the Internet and the technology foundation,ensures accurate location and retrieval of digital works,confirmming the copyright entity in network environment.The top priority is that DCI(digital copyright identifier) system must be established as soon as possible.On the concept and design principles of DCI,it analyses of relevant foreign research status,proposes coding scheme for copyright protection of our country's DCI,and gives encryption mechanisms in the mobile Internet application,digital certifi-cates,and DCI embedded program.Using the above method,it shows good compatibility,easy integration with the Interna-tional DOI(digital object identifier),encryption and digital certificates are designed for applications on the mobile Internet.%数字版权标志符为数字内容在互联网上提供唯一的版权身份标志,为确保在网络环境中能够精准定位和检索数字作品、确认版权主体提供了技术基础。建立数字版权标志符体系是我国数字版权管理发展的迫切要求。通过研究DCI(数字版权标志符)的概念、设计原则,分析了国外相关研究的现状,提出了适合我国版权保护的DCI编码方案,并给出了应用于移动互联网的加密机制、数字证书及DCI嵌入方案。研究结果表明,采用上述方法,兼容性好,易于与国际上的DOI(digital object identifier)接轨,加密机制及数字证书的设计适合在移动互联网上应用。

  3. Coded Path Protection: Efficient Conversion of Sharing to Coding

    CERN Document Server

    Avci, Serhat Nazim

    2011-01-01

    Link failures in wide area networks are common and cause significant data losses. Mesh-based protection schemes offer high capacity efficiency but they are slow and require complex signaling. Additionally, real-time reconfiguration of a cross-connect threatens their transmission integrity. On the other hand, coding-based protection schemes are proactive. Therefore, they have higher restoration speed, lower signaling complexity, and higher transmission integrity. This paper introduces a coding-based protection scheme, named Coded Path Protection (CPP). In CPP, a backup copy of the primary data is encoded with other data streams, resulting in capacity savings. This paper presents an optimal and simple capacity placement and coding group formation algorithm. The algorithm converts the sharing structure of any solution of a Shared Path Protection (SPP) technique into a coding structure with minimum extra capacity. We conducted quantitative and qualitative comparisons of our technique with the SPP and, another tec...

  4. Code of Ethics

    DEFF Research Database (Denmark)

    Adelstein, Jennifer; Clegg, Stewart

    2016-01-01

    Ethical codes have been hailed as an explicit vehicle for achieving more sustainable and defensible organizational practice. Nonetheless, when legal compliance and corporate governance codes are conflated, codes can be used to define organizational interests ostentatiously by stipulating norms...... for employee ethics. Such codes have a largely cosmetic and insurance function, acting subtly and strategically to control organizational risk management and protection. In this paper, we conduct a genealogical discourse analysis of a representative code of ethics from an international corporation...... to understand how management frames expectations of compliance. Our contribution is to articulate the problems inherent in codes of ethics, and we make some recommendations to address these to benefit both an organization and its employees. In this way, we show how a code of ethics can provide a foundation...

  5. Combustion chamber analysis code

    Science.gov (United States)

    Przekwas, A. J.; Lai, Y. G.; Krishnan, A.; Avva, R. K.; Giridharan, M. G.

    1993-05-01

    A three-dimensional, time dependent, Favre averaged, finite volume Navier-Stokes code has been developed to model compressible and incompressible flows (with and without chemical reactions) in liquid rocket engines. The code has a non-staggered formulation with generalized body-fitted-coordinates (BFC) capability. Higher order differencing methodologies such as MUSCL and Osher-Chakravarthy schemes are available. Turbulent flows can be modeled using any of the five turbulent models present in the code. A two-phase, two-liquid, Lagrangian spray model has been incorporated into the code. Chemical equilibrium and finite rate reaction models are available to model chemically reacting flows. The discrete ordinate method is used to model effects of thermal radiation. The code has been validated extensively against benchmark experimental data and has been applied to model flows in several propulsion system components of the SSME and the STME.

  6. Distributed space-time coding

    CERN Document Server

    Jing, Yindi

    2014-01-01

    Distributed Space-Time Coding (DSTC) is a cooperative relaying scheme that enables high reliability in wireless networks. This brief presents the basic concept of DSTC, its achievable performance, generalizations, code design, and differential use. Recent results on training design and channel estimation for DSTC and the performance of training-based DSTC are also discussed.

  7. Superdense Coding via Hot Trapped Ions

    Institute of Scientific and Technical Information of China (English)

    QIN Tao; FENG Mang; GAO Ke-Lin

    2004-01-01

    Superdense coding plays an important role in quantum information and can be performed with trapped ions. By confining the ions in a linear trap or a trap-cavity setup, we propose schemes to implement a reliable superdense coding by means of bichromatic radiation method. Experimental feasibility and reliability for achieving our schemes is discussed in detail.

  8. Improved code-tracking loop

    Science.gov (United States)

    Laflame, D. T.

    1980-01-01

    Delay-locked loop tracks pseudonoise codes without introducing dc timing errors, because it is not sensitive to gain imbalance between signal processing arms. "Early" and "late" reference codes pass in combined form through both arms, and each arm acts on both codes. Circuit accomodates 1 dB weaker input signals with tracking ability equal to that of tau-dither loops.

  9. Selection of Code and Interleaver for Turbo Coding

    DEFF Research Database (Denmark)

    Andersen, Jakob Dahl

    1998-01-01

    The selection of component codes for turbo coding has often been based on the performance at high SNR's. However, we will argue that the selection mainly should be based on the performance at low SNR's, i.e. the convergence properties. Further, we will present a way to construct interleavers...... that significantly improve the performance of the turbo coding scheme at high SNR's, i.e. lowers the error floor...

  10. An efficient medical image compression scheme.

    Science.gov (United States)

    Li, Xiaofeng; Shen, Yi; Ma, Jiachen

    2005-01-01

    In this paper, a fast lossless compression scheme is presented for the medical image. This scheme consists of two stages. In the first stage, a Differential Pulse Code Modulation (DPCM) is used to decorrelate the raw image data, therefore increasing the compressibility of the medical image. In the second stage, an effective scheme based on the Huffman coding method is developed to encode the residual image. This newly proposed scheme could reduce the cost for the Huffman coding table while achieving high compression ratio. With this algorithm, a compression ratio higher than that of the lossless JPEG method for image can be obtained. At the same time, this method is quicker than the lossless JPEG2000. In other words, the newly proposed algorithm provides a good means for lossless medical image compression.

  11. Very Low Bit-Rate Video Coding Using Motion ompensated 3-D Wavelet Transform

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A new motion-compensated 3-D wavelet transform (MC-3DWT) video coding scheme is presented in thispaper. The new coding scheme has a good performance in average PSNR, compression ratio and visual quality of re-constructions compared with the existing 3-D wavelet transform (3DWT) coding methods and motion-compensated2-D wavelet transform (MC-WT) coding method. The new MC-3DWT coding scheme is suitable for very low bit-rate video coding.

  12. A simple data compression scheme for binary images of bacteria compared with commonly used image data compression schemes

    NARCIS (Netherlands)

    Wilkinson, M.H.F.

    1994-01-01

    A run length code compression scheme of extreme simplicity, used for image storage in an automated bacterial morphometry system, is compared with more common compression schemes, such as are used in the tag image file format. These schemes are Lempel-Ziv and Welch (LZW), Macintosh Packbits, and CCIT

  13. Best Effort and Practice Activation Codes

    OpenAIRE

    Gans, G. de Koning; Verheul, E.

    2011-01-01

    Activation Codes are used in many different digital services and known by many different names including voucher, e-coupon and discount code. In this paper we focus on a specific class of ACs that are short, human-readable, fixed-length and represent value. Even though this class of codes is extensively used there are no general guidelines for the design of Activation Code schemes. We discuss different methods that are used in practice and propose BEPAC, a new Activation Code scheme that prov...

  14. Coding In-depth Semistructured Interviews

    DEFF Research Database (Denmark)

    Campbell, John L.; Quincy, Charles; Osserman, Jordan;

    2013-01-01

    Many social science studies are based on coded in-depth semistructured interview transcripts. But researchers rarely report or discuss coding reliability in this work. Nor is there much literature on the subject for this type of data. This article presents a procedure for developing coding schemes...

  15. Iterative Decoding of Parallel Concatenated Block Codes and Coset Based MAP Decoding Algorithm for F24 Code

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A multi-dimensional concatenation scheme for block codes is introduced, in which information symbols are interleaved and re-encoded for more than once. It provides a convenient platform to design high performance codes with flexible interleaver size.Coset based MAP soft-in/soft-out decoding algorithms are presented for the F24 code. Simulation results show that the proposed coding scheme can achieve high coding gain with flexible interleaver length and very low decoding complexity.

  16. Enhanced motion coding in MC-EZBC

    Science.gov (United States)

    Chen, Junhua; Zhang, Wenjun; Wang, Yingkun

    2005-07-01

    Since hierarchical variable size block matching and bidirectional motion compensation are used in the motioncompensated embedded zero block coding (MC-EZBC), the motion information consists of motion vector quadtree map and motion vectors. In the conventional motion coding scheme, the quadtree structure is coded directly, the motion vector modes are coded with Huffman codes, and the motion vector differences are coded by an m-ary arithmetic coder with 0-order models. In this paper we propose a new motion coding scheme which uses an extension of the CABAC algorithm and new context modeling for quadtree structure coding and mode coding. In addition, we use a new scalable motion coding method which scales the motion vector quadtrees according to the rate-distortion slope of the tree nodes. Experimental results show that the new coding scheme increases the efficiency of the motion coding by more than 25%. The performance of the system is improved accordingly, especially in low bit rates. Moreover, with the scalable motion coding, the subjective and objective coding performance is further enhanced in low bit rate scenarios.

  17. Dependency-aware unequal erasure protection codes

    Institute of Scientific and Technical Information of China (English)

    BOUABDALLAH Amine; LACAN Jér(o)me

    2006-01-01

    Classical unequal erasure protection schemes split data to be protected into classes which are encoded independently.The unequal protection scheme presented in this paper is based on an erasure code which encodes all the data together according to the existing dependencies. A simple algorithm generates dynamically the generator matrix of the erasure code according to the packets streams structure, i.e., the dependencies between the packets, and the rate of the code. This proposed erasure code was applied to a packetized MPEG4 stream transmitted over a packet erasure channel and compared with other classical protection schemes in terms of PSNR and MOS. It is shown that the proposed code allows keeping a high video quality-level in a larger packet loss rate range than the other protection schemes.

  18. An Advanced Threshold Secret Sharing Scheme for Identifying Cheaters

    Institute of Scientific and Technical Information of China (English)

    XIE Shu-cui; ZHANG Jian-zhong

    2003-01-01

    In this paper an advanced threshold secret sharing scheme for identifying cheaters is proposed by using authentication codes. The performance of the scheme is discussed. The results show that in the scheme the valid shareholders can not only identify the impersonation of an adversary, but also detect cheating of some valid shareholders. In particular one honest shareholder is able to detect cheating of other participants forming a collection, and the information rate of the scheme is higher than that of others.

  19. Quantum Communication Scheme Using Non-symmetric Quantum Channel

    Institute of Scientific and Technical Information of China (English)

    CAO Hai-Jing; CHEN Zhong-Hua; SONG He-Shan

    2008-01-01

    A theoretical quantum communication scheme based on entanglement swapping and superdense coding is proposed with a 3-dimensional Bell state and 2-dimensional Bell state function as quantum channel quantum key distribution and quantum secure direct communication can be simultaneously accomplished in the scheme. The scheme is secure and has high source capacity. At last, we generalize the quantum communication scheme to d-dimensional quantum channel.

  20. Coding Partitions

    Directory of Open Access Journals (Sweden)

    Fabio Burderi

    2007-05-01

    Full Text Available Motivated by the study of decipherability conditions for codes weaker than Unique Decipherability (UD, we introduce the notion of coding partition. Such a notion generalizes that of UD code and, for codes that are not UD, allows to recover the ``unique decipherability" at the level of the classes of the partition. By tacking into account the natural order between the partitions, we define the characteristic partition of a code X as the finest coding partition of X. This leads to introduce the canonical decomposition of a code in at most one unambiguouscomponent and other (if any totally ambiguouscomponents. In the case the code is finite, we give an algorithm for computing its canonical partition. This, in particular, allows to decide whether a given partition of a finite code X is a coding partition. This last problem is then approached in the case the code is a rational set. We prove its decidability under the hypothesis that the partition contains a finite number of classes and each class is a rational set. Moreover we conjecture that the canonical partition satisfies such a hypothesis. Finally we consider also some relationships between coding partitions and varieties of codes.

  1. Androgen-responsive non-coding small RNAs extend the potential of HCG stimulation to act as a bioassay of androgen sufficiency.

    Science.gov (United States)

    Rodie, M E; Mudaliar, M A V; Herzyk, P; McMillan, M; Boroujerdi, M; Chudleigh, S; Tobias, E S; Ahmed, S F

    2017-10-01

    It is unclear whether a short-term change in circulating androgens is associated with changes in the transcriptome of the peripheral blood mononuclear cells (PBMC). To explore the effect of hCG stimulation on the PBMC transcriptome, 12 boys with a median age (range) of 0.7 years (0.3, 11.2) who received intramuscular hCG 1500u on 3 consecutive days as part of their investigations underwent transcriptomic array analysis on RNA extracted from peripheral blood mononuclear cells before and after hCG stimulation. Median pre- and post-hCG testosterone for the overall group was 0.7 nmol/L (hCG stimulation with a pre and post median serum testosterone of hCG effects, all 9 of the hCG responders consistently demonstrated a 20% or greater increase in the expression of piR-37153 and piR-39248, non-coding PIWI-interacting RNAs (piRNAs). In addition, of the 9 responders, 8, 6 and 4 demonstrated a 30, 40 and 50% rise, respectively, in a total of 2 further piRNAs. In addition, 3 of the responders showed a 50% or greater rise in the expression of another small RNA, SNORD5. On comparing fold-change in serum testosterone with fold-change in the above transcripts, a positive correlation was detected for SNORD5 (P = 0.01). The identification of a dynamic and androgen-responsive PBMC transcriptome extends the potential value of the hCG test for the assessment of androgen sufficiency. © 2017 The authors.

  2. Site-directed RNA editing by adenosine deaminase acting on RNA (ADAR1) for correction of the genetic code in gene therapy.

    Science.gov (United States)

    Azad, T A; Bhakta, S; Tsukahara, T

    2017-10-06

    Site-directed RNA editing is an important technique for correcting gene sequences and ultimately tuning protein function. In this study, we engineered the deaminase domain of adenosine deaminase acting on RNA (ADAR1) and the MS2 system to target specific adenosines, with the goal of correcting G-to-A mutations at the RNA level. For this purpose, the ADAR1 deaminase domain was fused downstream of the RNA-binding protein MS2, which has affinity for the MS2 RNA. To direct editing to specific targets, we designed guide RNAs complementary to target RNAs. The guide RNAs directed the ADAR1 deaminase to the desired editing site, where it converted adenosine to inosine. To provide proof of principle, we used an allele of EGFP bearing a mutation at the 58th amino acid (TGG), encoding Trp, into an amber (TAG) or ochre (TAA) stop codon. In HEK-293 cells, our system could convert stop codons to read-through codons, thereby turning on fluorescence. We confirmed the specificity of editing at the DNA level by restriction fragment length polymorphism (RFLP) analysis and sequencing, and at the protein level by western blotting. The editing efficiency of this enzyme system was ~5%. We believe that this system could be used to treat genetic diseases resulting from G-to-A point mutations.Gene Therapy accepted article preview online, 06 October 2017. doi:10.1038/gt.2017.90.

  3. Pragmatic Approach to Adaptive Turbo Coded Modulation

    Institute of Scientific and Technical Information of China (English)

    左健存; 宋文涛; 罗汉文; 徐友云

    2003-01-01

    This paper presents a pragmatic adaptive scheme for TuCM over slowly fading channels. The adaptive scheme employs a single turbo coded modulator composed of a variable-rate turbo encoder and a variable-rate variable-power MQAM for all fading regions, so it has an acceptable complexity to implement. The optimal adaptive TuCM scheme is determined subject to various system constraints. Simulations have been performed to measure the performance of the scheme for different parameters. It is shown that adopting both the turbo coded modulator and the transmit power achieves a performance within 2.5 dB of the fading channel capacity.

  4. A MIMO Cross-layer Security Scheme based on STTC Deformation Code%一种基于STTC变形码的MIMO跨层安全研究方案∗

    Institute of Scientific and Technical Information of China (English)

    宋欢欢; 唐杰; 文红; 向达; 廖润发

    2014-01-01

    用于高速无线通信的空时网格码,能够达到频谱利用率、分集增益与编码复杂度之间的最佳折中,是一种最佳空时码。文中提出在STTC系统中设计一种STTC变形码并将其与上层密码技术结合,充分利用信道的有噪特性,可以实现增强的无线通讯加密方式,防止信息泄露。%STTC (space-time trellis code),as an optimal space-time codes applied in high-speed wireless communication,can a-chieve the best tradeoff among spectrum efficiency,diversity gain,and encoding complexity. This paper proposes a STTC deformation code in combination with upper layer encryption technique. It takes full advantage of noisy channel characteristics and could thus en-hance the encryption of wireless communication and prevent information leakage.

  5. Video Coding with Motion-Compensated Lifted Wavelet Transforms

    OpenAIRE

    Flierl, M.; Girod, B.

    2004-01-01

    This article explores the efficiency of motion-compensated three-dimensional transform coding, a compression scheme that employs a motion-compensated transform for a group of pictures. We investigate this coding scheme experimentally and theoretically. The practical coding scheme employs in temporal direction a wavelet decomposition with motion-compensated lifting steps. Further, we compare the experimental results to that of a predictive video codec with single-hypothesis motion compensation...

  6. Packet combining based on cross-packet coding

    Institute of Scientific and Technical Information of China (English)

    LIN DengSheng; XIAO Ming; LI ShaoQian

    2013-01-01

    We propose a packet combining scheme of using cross-packet coding. With the coding scheme, one redundant packet can be used to ensure the error-correction of multiple source packets. Thus, the proposed scheme can increase the code rate. Moreover, the proposed coding scheme has also advantages of decoding complexity, reducing undetectable errors (by the proposed low-complexity decoder) and flexibility (applicable to channels with and without feedback). Theoretical analysis under the proposed low-complexity decoding algorithm is given to maximize the code rate by optimizing the number of source packets. Finally, we give numerical results to demonstrate the advantages of the proposed scheme in terms of code rates compared to the traditional packet combining without coding or ARQ (automatic repeat-request) techniques.

  7. Efficient and Universal Corruption Resilient Fountain Codes

    CERN Document Server

    Cohen, Asaf; Tzachar, Nir

    2011-01-01

    In this paper, we present a new family of fountain codes which overcome adversarial errors. That is, we consider the possibility that some portion of the arriving packets of a rateless erasure code are corrupted in an undetectable fashion. In practice, the corrupted packets may be attributed to a portion of the communication paths which are controlled by an adversary or to a portion of the sources that are malicious. The presented codes resemble and extend LT and Raptor codes. Yet, their benefits over existing coding schemes are manifold. First, to overcome the corrupted packets, our codes use information theoretic techniques, rather than cryptographic primitives. Thus, no secret channel between the senders and the receivers is required. Second, the encoders in the suggested scheme are oblivious to the strength of the adversary, yet perform as if its strength was known in advance. Third, the sparse structure of the codes facilitates efficient decoding. Finally, the codes easily fit a decentralized scenario wi...

  8. ComboCoding: Combined intra-/inter-flow network coding for TCP over disruptive MANETs

    Directory of Open Access Journals (Sweden)

    Chien-Chia Chen

    2011-07-01

    Full Text Available TCP over wireless networks is challenging due to random losses and ACK interference. Although network coding schemes have been proposed to improve TCP robustness against extreme random losses, a critical problem still remains of DATA–ACK interference. To address this issue, we use inter-flow coding between DATA and ACK to reduce the number of transmissions among nodes. In addition, we also utilize a “pipeline” random linear coding scheme with adaptive redundancy to overcome high packet loss over unreliable links. The resulting coding scheme, ComboCoding, combines intra-flow and inter-flow coding to provide robust TCP transmission in disruptive wireless networks. The main contributions of our scheme are twofold; the efficient combination of random linear coding and XOR coding on bi-directional streams (DATA and ACK, and the novel redundancy control scheme that adapts to time-varying and space-varying link loss. The adaptive ComboCoding was tested on a variable hop string topology with unstable links and on a multipath MANET with dynamic topology. Simulation results show that TCP with ComboCoding delivers higher throughput than with other coding options in high loss and mobile scenarios, while introducing minimal overhead in normal operation.

  9. Scalable motion vector coding

    Science.gov (United States)

    Barbarien, Joeri; Munteanu, Adrian; Verdicchio, Fabio; Andreopoulos, Yiannis; Cornelis, Jan P.; Schelkens, Peter

    2004-11-01

    Modern video coding applications require transmission of video data over variable-bandwidth channels to a variety of terminals with different screen resolutions and available computational power. Scalable video coding is needed to optimally support these applications. Recently proposed wavelet-based video codecs employing spatial domain motion compensated temporal filtering (SDMCTF) provide quality, resolution and frame-rate scalability while delivering compression performance comparable to that of the state-of-the-art non-scalable H.264-codec. These codecs require scalable coding of the motion vectors in order to support a large range of bit-rates with optimal compression efficiency. Scalable motion vector coding algorithms based on the integer wavelet transform followed by embedded coding of the wavelet coefficients were recently proposed. In this paper, a new and fundamentally different scalable motion vector codec (MVC) using median-based motion vector prediction is proposed. Extensive experimental results demonstrate that the proposed MVC systematically outperforms the wavelet-based state-of-the-art solutions. To be able to take advantage of the proposed scalable MVC, a rate allocation mechanism capable of optimally dividing the available rate among texture and motion information is required. Two rate allocation strategies are proposed and compared. The proposed MVC and rate allocation schemes are incorporated into an SDMCTF-based video codec and the benefits of scalable motion vector coding are experimentally demonstrated.

  10. Exploiting Same Scale Similarity in Fisher's Scheme

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yao

    2001-01-01

    The method proposed by Y. Fisher is the most popular fractal image coding scheme. In his scheme, domain blocks are constrained to be twice as large as range blocks in order to ensure the convergence of the iterative decoding stage. However,this constraint has limited the fractal encoder to exploit the self-similarity of the original image. In order to overcome the shortcoming, a novel scheme using same-sized range and domain blocks is proposed in the paper. Experimental results show the improvements in compression performance.

  11. DESCRIPCIÓN MODULAR DE UN ESQUEMA DE CODIFICACIÓN CONCATENADO PARA CORRECCIÓN DE ERRORES CON PROGRAMACIÓN DE HARDWARE MODULAR DESIGN OF SCHEME CODING CONCATENATED FOR CORRECTION ERROR WITH PROGRAMMING OF HARDWARE

    Directory of Open Access Journals (Sweden)

    Cecilia E Sandoval Ruiz

    2008-09-01

    Full Text Available Las comunicaciones inalámbricas requieren el empleo de métodos de corrección de errores sobre los datos transmitidos, usándose generalmente técnicas de codificación Reed-Solomon & Viterbi, por razones de desempeño y seguridad es preferible implementarlos sobre hardware. En este trabajo se presenta el diseño modular de la etapa de codificación de éstos códigos para su concatenación usando VHDL (VHSIC Hardware Descriptor Language, orientado a la implementación sobre tecnología de matriz de compuertas programadas por campo (FPGA, Se inicia con una revisión de los conceptos asociados a la definición de los componentes, y el modelo, descripción del comportamiento, luego la arquitectura es diseñada usando la sintaxis en VHDL y es capturado el diseño de hardware, finalmente se presentan los resultados de síntesis.The wireless communication medium require employing forward error correction methods on the data transferred, where Reed-Solomon & Viterbi coding techniques are utilized, because of performance and security reaso. In this paper we present a modular design of phase encoding these codes for concatenation using VHDL (VHSIC Hardware Descriptor Language and oriented to implementation with field programmable gate arrays (FPGA. The work besing with a review of code concept and the definition of the components and the model and the description of the behavioral. Later, the architecture is designed and captures using syntax in VHDL, and finally presents the results of synthesis.

  12. Interleaver Design for Turbo Coding

    DEFF Research Database (Denmark)

    Andersen, Jakob Dahl; Zyablov, Viktor

    1997-01-01

    By a combination of construction and random search based on a careful analysis of the low weight words and the distance properties of the component codes, it is possible to find interleavers for turbo coding with a high minimum distance. We have designed a block interleaver with permutations...... of each row, and found a combination of permutations where a tight upper bound to the minimum distance of the complete turbo scheme is 108....

  13. Optical code division multiple access secure communications systems with rapid reconfigurable polarization shift key user code

    Science.gov (United States)

    Gao, Kaiqiang; Wu, Chongqing; Sheng, Xinzhi; Shang, Chao; Liu, Lanlan; Wang, Jian

    2015-09-01

    An optical code division multiple access (OCDMA) secure communications system scheme with rapid reconfigurable polarization shift key (Pol-SK) bipolar user code is proposed and demonstrated. Compared to fix code OCDMA, by constantly changing the user code, the performance of anti-eavesdropping is greatly improved. The Pol-SK OCDMA experiment with a 10 Gchip/s user code and a 1.25 Gb/s user data of payload has been realized, which means this scheme has better tolerance and could be easily realized.

  14. Construction of Capacity Achieving Lattice Gaussian Codes

    KAUST Repository

    Alghamdi, Wael

    2016-04-01

    We propose a new approach to proving results regarding channel coding schemes based on construction-A lattices for the Additive White Gaussian Noise (AWGN) channel that yields new characterizations of the code construction parameters, i.e., the primes and dimensions of the codes, as functions of the block-length. The approach we take introduces an averaging argument that explicitly involves the considered parameters. This averaging argument is applied to a generalized Loeliger ensemble [1] to provide a more practical proof of the existence of AWGN-good lattices, and to characterize suitable parameters for the lattice Gaussian coding scheme proposed by Ling and Belfiore [3].

  15. Magnetohydrodynamic Simulation Code CANS+: Assessments and Applications

    CERN Document Server

    Matsumoto, Yosuke; Kudoh, Yuki; Kawashima, Tomohisa; Matsumoto, Jin; Takahashi, Hiroyuki R; Minoshima, Takashi; Zenitani, Seiji; Miyoshi, Takahiro; Matsumoto, Ryoji

    2016-01-01

    We present a new magnetohydrodynamic (MHD) simulation code with the aim of providing accurate numerical solutions to astrophysical phenomena where discontinuities, shock waves, and turbulence are inherently important. The code implements the HLLD approximate Riemann solver, the fifth-order-monotonicity-preserving interpolation scheme, and the hyperbolic divergence cleaning method for a magnetic field. This choice of schemes significantly improved numerical accuracy and stability, and saved computational costs in multidimensional problems. Numerical tests of one- and two-dimensional problems showed the advantages of using the high-order scheme by comparing with results from a standard second-order TVD scheme. The present code enabled us to explore long-term evolution of a three-dimensional global accretion disk, in which compressible MHD turbulence saturated at much higher levels via the magneto-rotational instability than that given by the second-order scheme owing to the adoption of the high-resolution, nume...

  16. Holographic codes

    CERN Document Server

    Latorre, Jose I

    2015-01-01

    There exists a remarkable four-qutrit state that carries absolute maximal entanglement in all its partitions. Employing this state, we construct a tensor network that delivers a holographic many body state, the H-code, where the physical properties of the boundary determine those of the bulk. This H-code is made of an even superposition of states whose relative Hamming distances are exponentially large with the size of the boundary. This property makes H-codes natural states for a quantum memory. H-codes exist on tori of definite sizes and get classified in three different sectors characterized by the sum of their qutrits on cycles wrapped through the boundaries of the system. We construct a parent Hamiltonian for the H-code which is highly non local and finally we compute the topological entanglement entropy of the H-code.

  17. Sharing code

    OpenAIRE

    Kubilius, Jonas

    2014-01-01

    Sharing code is becoming increasingly important in the wake of Open Science. In this review I describe and compare two popular code-sharing utilities, GitHub and Open Science Framework (OSF). GitHub is a mature, industry-standard tool but lacks focus towards researchers. In comparison, OSF offers a one-stop solution for researchers but a lot of functionality is still under development. I conclude by listing alternative lesser-known tools for code and materials sharing.

  18. Very low bit streaming image compression coder based on lift scheme

    Science.gov (United States)

    Tao, Hongjiu; Tian, Jinwen; Liu, Jianguo; Yu, Qiuzhe; Xu, Hongbo

    2001-09-01

    This paper presents a novel compression encoding/decoding method based on lift scheme for I-VOP. In traditional coding I-VOP algorithm, the textures and shapes are separately coded, and the macro-block DCT coding method is adopted in the coding texture and 16x16 BAB(Binary Alpha Block) coding method is employed in shape coding. The texture and shape coding method is not of embed feature. The algorithm based on lift scheme for I-VOP, the texture and shape at same time is coded and the bit streaming is of embed feature.

  19. Toric Codes, Multiplicative Structure and Decoding

    DEFF Research Database (Denmark)

    Hansen, Johan Peder

    2017-01-01

    Long linear codes constructed from toric varieties over finite fields, their multiplicative structure and decoding. The main theme is the inherent multiplicative structure on toric codes. The multiplicative structure allows for \\emph{decoding}, resembling the decoding of Reed-Solomon codes...... and aligns with decoding by error correcting pairs. We have used the multiplicative structure on toric codes to construct linear secret sharing schemes with \\emph{strong multiplication} via Massey's construction generalizing the Shamir Linear secret sharing shemes constructed from Reed-Solomon codes. We have...... constructed quantum error correcting codes from toric surfaces by the Calderbank-Shor-Steane method....

  20. LDPC-coded unitary space-time modulation with low-complexity iterative demodulate-decoding scheme%具有低复杂度的LDPC已编码非相干酉空时调制系统设计

    Institute of Scientific and Technical Information of China (English)

    王利娇; 张林; 杨玲玲; 彭立; 符达伟

    2014-01-01

    提出一种克服无线信道瑞利衰落和高斯白噪声干扰的非相干编码调制MIMO系统方案。纠错码采用IEEE 802.16e 中的非规则 QC-LDPC 码,非相干调制采用基于三角函数的酉空时调制(SC-USTM)。在接收端,推导出SC-USTM的最大后验概率(MAP)解调算法;为了降低复杂度,构造了SC-USTM 的双解调器方案;为了改善双解调的性能,在置信传播(BP)迭代解码器和MAP解调器之间引入了迭代反馈机制。仿真实验表明LDPC已编码SC-USTM的MIMO系统比未编码USTM的MIMO系统在510-误码率时,性能改善15~17 dB,并且整个系统具有较低的计算复杂度。%A practical low-density parity-check(LDPC) coded unitary space-time modulation (USTM) noncoherent MI-MO communication system over Rayleigh flat fading and additive white Gaussian noise (AWGN) channel was con-structed, where the LDPC code is selected from IEEE 802.16e Standard and USTM is constructed by the unitary matrix based on the sinc-cosinc function, SC-USTM for short. At the receiver, the maximum a posteriori probability (MAP) de-modulating algorithm of the SC-USTM was first designed;for reducing the complexity of MAP demodulator, the dual demodulator was then conceived;for improving the performance, the iterative feedback between the belief propagation (BP) decoder and the MPA demodulator was finally introduced. The simulation test shows that the system of the 510-LDPC coded SC-USTM is superior to the uncoded SC-USTM about 15~17 dB at BER , and this system has very low complexity.

  1. Calculation of the dielectric constant ɛ and first nonlinear susceptibility χ(2) of crystalline potassium dihydrogen phosphate by the coupled perturbed Hartree-Fock and coupled perturbed Kohn-Sham schemes as implemented in the CRYSTAL code

    Science.gov (United States)

    Lacivita, Valentina; Rérat, Michel; Kirtman, Bernard; Ferrero, Mauro; Orlando, Roberto; Dovesi, Roberto

    2009-11-01

    The high-frequency dielectric ɛ and the first nonlinear electric susceptibility χ(2) tensors of crystalline potassium dihydrogen phosphate (KH2PO4) are calculated by using the coupled perturbed Hartree-Fock and Kohn-Sham methods as implemented in the CRYSTAL code. The effect of basis sets of increasing size on ɛ and χ(2) is explored. Five different levels of theory, namely, local-density approximation, generalized gradient approximation (PBE), hybrids (B3LYP and PBE0), and HF are compared using the experimental and theoretical structures corresponding not only to the tetragonal geometry I4d2 at room temperature but also to the orthorhombic phase Fdd2 at low temperature. Comparison between the two phases and their optical behavior is made. The calculated results for the tetragonal phase are in good agreement with the experimental data.

  2. Lossless quantum coding in many-letter spaces

    CERN Document Server

    Boström, K J

    2000-01-01

    Based on the concept of many-letter theory a general characterization of quantum codes using the Kraus representation is given. Compression codes are defined by their property of decreasing the average information content of a given a priori message ensemble. Lossless quantum codes, in contrast to lossy codes, provide the retrieval of the original input states with perfect fidelity. A general lossless coding scheme is given that translates between two quantum alphabets. It is shown that this scheme is never compressive. Furthermore, a lossless quantum coding scheme, analog to the classical Huffman scheme but different from the Braunstein scheme, is implemented, which provides optimal compression. Motivated by the concept of lossless quantum compression, an observable is defined that measures the amount of compressible quantum information contained in a particular message with respect to a given \\emph{a priori} message ensemble. The average of this observable yields the von Neumann entropy, which is finally es...

  3. Generalized Group Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The concept of generalized group signature scheme will bepresent. Based on the generalized secret sharing scheme proposed by Lin and Ha rn, a non-interactive approach is designed for realizing such generalized group signature scheme. Using the new scheme, the authorized subsets of the group in w hich the group member can cooperate to produce the valid signature for any messa ge can be randomly specified

  4. Puncturing Period on the Performance of Punctured Turbo Codes

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Puncturing is the predominant strategy to construct high code rate turbo codes. Puncturing period is a crucial parameter influencing the performance of punctured turbo codes (PTC). Here we developed a new puncturing scheme of turbo codes, with which the puncturing period on the performance of PTC is studied. Consequently, suggestions on selecting the puncturing period are proposed.

  5. ARQ for Network Coding

    CERN Document Server

    Sundararajan, Jay Kumar; Médard, Muriel

    2008-01-01

    A new coding and queue management algorithm is proposed for communication networks that employ linear network coding. The algorithm has the feature that the encoding process is truly online, as opposed to a block-by-block approach. The setup assumes a packet erasure broadcast channel with stochastic arrivals and full feedback, but the proposed scheme is potentially applicable to more general lossy networks with link-by-link feedback. The algorithm guarantees that the physical queue size at the sender tracks the backlog in degrees of freedom (also called the virtual queue size). The new notion of a node "seeing" a packet is introduced. In terms of this idea, our algorithm may be viewed as a natural extension of ARQ schemes to coded networks. Our approach, known as the drop-when-seen algorithm, is compared with a baseline queuing approach called drop-when-decoded. It is shown that the expected queue size for our approach is $O(\\frac1{1-\\rho})$ as opposed to $\\Omega(\\frac1{(1-\\rho)^2})$ for the baseline approach...

  6. Finite Boltzmann schemes

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2006-01-01

    In the special case of relaxation parameter = 1 lattice Boltzmann schemes for (convection) diffusion and fluid flow are equivalent to finite difference/volume (FD) schemes, and are thus coined finite Boltzmann (FB) schemes. We show that the equivalence is inherent to the homology of the

  7. MIDI Programming in Scheme

    DEFF Research Database (Denmark)

    Nørmark, Kurt

    2010-01-01

    A Scheme representation of Standard MIDI Files is proposed. The Scheme expressions are defined and constrained by an XML-language, which in the starting point is inspired by a MIDI XML event language made by the MIDI Manufactures Association. The representation of Standard MIDI Files in Scheme ma...

  8. MIDI Programming in Scheme

    DEFF Research Database (Denmark)

    Nørmark, Kurt

    2010-01-01

    A Scheme representation of Standard MIDI Files is proposed. The Scheme expressions are defined and constrained by an XML-language, which in the starting point is inspired by a MIDI XML event language made by the MIDI Manufactures Association. The representation of Standard MIDI Files in Scheme ma...

  9. Language Recognition via Sparse Coding

    Science.gov (United States)

    2016-09-08

    target language lT ) from the two pipelines. We can also think of more sophis- ticated fusion schemes on logistic regression and neural net - works. Table...vol. 16, no. 5, pp. 980–988, July 2008. [6] G. Sivaram, S. K. Nemala, M. Elhilali, T. D. Tran, and H. Herman- sky , “Sparse Coding for Speech

  10. Speaking Code

    DEFF Research Database (Denmark)

    Cox, Geoff

    Speaking Code begins by invoking the “Hello World” convention used by programmers when learning a new language, helping to establish the interplay of text and code that runs through the book. Interweaving the voice of critical writing from the humanities with the tradition of computing and software...

  11. Polar Codes

    Science.gov (United States)

    2014-12-01

    QPSK Gaussian channels . .......................................................................... 39 vi 1. INTRODUCTION Forward error correction (FEC...Capacity of BSC. 7 Figure 5. Capacity of AWGN channel . 8 4. INTRODUCTION TO POLAR CODES Polar codes were introduced by E. Arikan in [1]. This paper...Under authority of C. A. Wilgenbusch, Head ISR Division EXECUTIVE SUMMARY This report describes the results of the project “More reliable wireless

  12. Quantum election scheme based on anonymous quantum key distribution

    Institute of Scientific and Technical Information of China (English)

    Zhou Rui-Rui; Yang Li

    2012-01-01

    An unconditionally secure authority-certified anonymous quantum key distribution scheme using conjugate coding is presented,based on which we construct a quantum election scheme without the help of an entanglement state.We show that this election scheme ensures the completeness,soundness,privacy,eligibility,unreusability,fairness,and verifiability of a large-scale election in which the administrator and counter are semi-honest.This election scheme can work even if there exist loss and errors in quantum channels.In addition,any irregularity in this scheme is sensible.

  13. An Achievability Scheme for the Compound Channel with State Noncausally Available at the Encoder

    CERN Document Server

    Nair, Chandra; Chia, Yeow-Khiang

    2010-01-01

    A new achievability scheme for the compound channel with discrete memoryless (DM) state noncausally available at the encoder is established. Achievability is proved using superposition coding, Marton coding, joint typicality encoding, and indirect decoding. The scheme is shown to achieve strictly higher rate than the straightforward extension of the Gelfand-Pinsker coding scheme for a single DMC with DM state, and is optimal for some classes of channels.

  14. Improved vector quantization scheme for grayscale image compression

    Science.gov (United States)

    Hu, Y.-C.; Chen, W.-L.; Lo, C.-C.; Chuang, J.-C.

    2012-06-01

    This paper proposes an improved image coding scheme based on vector quantization. It is well known that the image quality of a VQ-compressed image is poor when a small-sized codebook is used. In order to solve this problem, the mean value of the image block is taken as an alternative block encoding rule to improve the image quality in the proposed scheme. To cut down the storage cost of compressed codes, a two-stage lossless coding approach including the linear prediction technique and the Huffman coding technique is employed in the proposed scheme. The results show that the proposed scheme achieves better image qualities than vector quantization while keeping low bit rates.

  15. A New Scheme of Speech Coding Based on Compressed Sensing and Sinusoidal Dictionary%基于压缩感知和正弦字典的语音编码新方案

    Institute of Scientific and Technical Information of China (English)

    李尚靖; 朱琦; 朱俊华

    2015-01-01

    A novel speech coding method based on compressed sensing is proposed in this paper. Based on compressed sensing theory,the row echelon matrix retains parts of speech time domain features in the measurements,and utilize a sinusoidal dictionary and matching pur-suit for measurements sequence modeling. The model parameters are encoded by appropriate methods respectively. At the decoder,basis pursuit algorithm employs the decoded measurements for synthesized speech reconstruction. A rear low-pass filter is adopted to improve auditory effects. Simulation results show the average MOS scores of the synthesis speech are between 2. 81~3. 23 in low bit rate (2. 8~5. 7 kbps),which achieves a preferable coding effect in compressed sensing framework.%文中提出一种压缩感知框架采样下的语音编码方案。根据压缩感知原理,利用行阶梯矩阵投影产生的观测序列保留了部分语音信息的时域特征,利用正弦字典和匹配追踪算法对观测序列进行建模,对于每帧观测序列的模型参数,根据各自特性采用合适的编码方式进行编码。在解码端对解码后的观测序列利用基追踪算法重构合成语音,并后置低通滤波器提高合成语音的人耳听觉效果。仿真实验表明,提出的编码方案在2.8~5.7 kbps时得到的合成语音平均MOS分为2.81~3.23,在压缩感知框架下取得了较好的语音编码效果。

  16. Trajectory Codes for Flash Memory

    CERN Document Server

    Anxiao,; Langberg, Michael; Schwartz, Moshe; Bruck, Jehoshua

    2010-01-01

    Flash memory is well-known for its inherent asymmetry: the flash-cell charge levels are easy to increase but are hard to decrease. In a general rewriting model, the stored data changes its value with certain patterns. The patterns of data updates are determined by the data structure and the application, and are independent of the constraints imposed by the storage medium. Thus, an appropriate coding scheme is needed so that the data changes can be updated and stored efficiently under the storage-medium's constraints. In this paper, we define the general rewriting problem using a graph model. It extends many known rewriting models such as floating codes, WOM codes, buffer codes, etc. We present a new rewriting scheme for flash memories, called the trajectory code, for rewriting the stored data as many times as possible without block erasures. We prove that the trajectory code is asymptotically optimal in a wide range of scenarios. We also present randomized rewriting codes optimized for expected performance (g...

  17. Scheme Program Documentation Tools

    DEFF Research Database (Denmark)

    Nørmark, Kurt

    2004-01-01

    This paper describes and discusses two different Scheme documentation tools. The first is SchemeDoc, which is intended for documentation of the interfaces of Scheme libraries (APIs). The second is the Scheme Elucidator, which is for internal documentation of Scheme programs. Although the tools...... are separate and intended for different documentation purposes they are related to each other in several ways. Both tools are based on XML languages for tool setup and for documentation authoring. In addition, both tools rely on the LAML framework which---in a systematic way---makes an XML language available...

  18. A Pixel Domain Video Coding based on Turbo code and Arithmetic code

    Directory of Open Access Journals (Sweden)

    Cyrine Lahsini

    2012-05-01

    Full Text Available In recent years, with emerging applications such as multimedia sensors networks, wirelesslow-power surveillance and mobile camera phones, the traditional video coding architecture in beingchallenged. In fact, these applications have different requirements than those of the broadcast videodelivery systems: a low power consumption at the encoder side is essential.In this context, we propose a pixel-domain video coding scheme which fits well in these senarios.In this system, both the arithmetic and turbo codes are used to encode the video sequence's frames.Simulations results show significant gains over Pixel-domain Wyner-Ziv video codeingr.

  19. Distributed source coding of video

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Van Luong, Huynh

    2015-01-01

    A foundation for distributed source coding was established in the classic papers of Slepian-Wolf (SW) [1] and Wyner-Ziv (WZ) [2]. This has provided a starting point for work on Distributed Video Coding (DVC), which exploits the source statistics at the decoder side offering shifting processing...... steps, conventionally performed at the video encoder side, to the decoder side. Emerging applications such as wireless visual sensor networks and wireless video surveillance all require lightweight video encoding with high coding efficiency and error-resilience. The video data of DVC schemes differ from...... the assumptions of SW and WZ distributed coding, e.g. by being correlated in time and nonstationary. Improving the efficiency of DVC coding is challenging. This paper presents some selected techniques to address the DVC challenges. Focus is put on pin-pointing how the decoder steps are modified to provide...

  20. Distributed source coding of video

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Van Luong, Huynh

    2015-01-01

    steps, conventionally performed at the video encoder side, to the decoder side. Emerging applications such as wireless visual sensor networks and wireless video surveillance all require lightweight video encoding with high coding efficiency and error-resilience. The video data of DVC schemes differ from......A foundation for distributed source coding was established in the classic papers of Slepian-Wolf (SW) [1] and Wyner-Ziv (WZ) [2]. This has provided a starting point for work on Distributed Video Coding (DVC), which exploits the source statistics at the decoder side offering shifting processing...... the assumptions of SW and WZ distributed coding, e.g. by being correlated in time and nonstationary. Improving the efficiency of DVC coding is challenging. This paper presents some selected techniques to address the DVC challenges. Focus is put on pin-pointing how the decoder steps are modified to provide...

  1. Binary Error Correcting Network Codes

    CERN Document Server

    Wang, Qiwen; Li, Shuo-Yen Robert

    2011-01-01

    We consider network coding for networks experiencing worst-case bit-flip errors, and argue that this is a reasonable model for highly dynamic wireless network transmissions. We demonstrate that in this setup prior network error-correcting schemes can be arbitrarily far from achieving the optimal network throughput. We propose a new metric for errors under this model. Using this metric, we prove a new Hamming-type upper bound on the network capacity. We also show a commensurate lower bound based on GV-type codes that can be used for error-correction. The codes used to attain the lower bound are non-coherent (do not require prior knowledge of network topology). The end-to-end nature of our design enables our codes to be overlaid on classical distributed random linear network codes. Further, we free internal nodes from having to implement potentially computationally intensive link-by-link error-correction.

  2. Code Optimization in FORM

    CERN Document Server

    Kuipers, J; Vermaseren, J A M

    2013-01-01

    We describe the implementation of output code optimization in the open source computer algebra system FORM. This implementation is based on recently discovered techniques of Monte Carlo tree search to find efficient multivariate Horner schemes, in combination with other optimization algorithms, such as common subexpression elimination. For systems for which no specific knowledge is provided it performs significantly better than other methods we could compare with. Because the method has a number of free parameters, we also show some methods by which to tune them to different types of problems.

  3. Topological code Autotune

    CERN Document Server

    Fowler, Austin G; McInnes, Angus L; Rabbani, Alimohammad

    2012-01-01

    Tailoring a fault-tolerant quantum error correction scheme to a specific physical architecture can be a laborious task. We describe a tool Autotune capable of analyzing and optimizing the classical processing for an arbitrary 2-D qubit architecture making use of arbitrary circuits implementing either the surface code or progressively generated slices of a 3-D topological cluster state with arbitrary stochastic error models for each quantum gate. Autotune is designed to facilitate precise study of the performance of real hardware running topological quantum error correction.

  4. Tree Coding of Bilevel Images

    DEFF Research Database (Denmark)

    Martins, Bo; Forchhammer, Søren

    1998-01-01

    Presently, sequential tree coders are the best general purpose bilevel image coders and the best coders of halftoned images. The current ISO standard, Joint Bilevel Image Experts Group (JBIG), is a good example. A sequential tree coder encodes the data by feeding estimates of conditional...... probabilities to an arithmetic coder. The conditional probabilities are estimated from co-occurrence statistics of past pixels, the statistics are stored in a tree. By organizing the code length calculations properly, a vast number of possible models (trees) reflecting different pixel orderings can...... is one order of magnitude slower than JBIG, obtains excellent and highly robust compression performance. A multipass free tree coding scheme produces superior compression results for all test images. A multipass free template coding scheme produces significantly better results than JBIG for difficult...

  5. Sudan-decoding generalized geometric Goppa codes

    DEFF Research Database (Denmark)

    Heydtmann, Agnes Eileen

    2003-01-01

    Generalized geometric Goppa codes are vector spaces of n-tuples with entries from different extension fields of a ground field. They are derived from evaluating functions similar to conventional geometric Goppa codes, but allowing evaluation in places of arbitrary degree. A decoding scheme...

  6. 'Turbo' coding for deep space applications

    DEFF Research Database (Denmark)

    Andersen, Jakob Dahl

    1995-01-01

    The performance of the `turbo' coding scheme is measured and an error floor is discovered. These residual errors are corrected with an outer BCH code. The complexity of the system is discussed, and for low data rates a realizable system operating at Eb/N0 below 0.2 dB is presented...

  7. Continuous-variable quantum erasure correcting code

    DEFF Research Database (Denmark)

    Lassen, Mikael Østergaard; Sabuncu, Metin; Huck, Alexander

    2010-01-01

    We experimentally demonstrate a continuous variable quantum erasure-correcting code, which protects coherent states of light against complete erasure. The scheme encodes two coherent states into a bi-party entangled state, and the resulting 4-mode code is conveyed through 4 independent channels...

  8. Bandwidth-Efficient Cooperative Relaying Schemes with Multiantenna Relay

    Directory of Open Access Journals (Sweden)

    Tho Le-Ngoc

    2008-05-01

    Full Text Available We propose coded cooperative relaying schemes in which all successfully decoded signals from multiple sources are forwarded simultaneously by a multiantenna relay to a common multiantenna destination to increase bandwidth efficiency. These schemes facilitate various retransmission strategies at relay and single-user and multiuser iterative decoding techniques at destination, suitable for trade-offs between performance, latency, and complexity. Simulation results show that the proposed schemes significantly outperform direct transmission under the same transmit power and bandwidth efficiency.

  9. Convertible Proxy Signcryption Scheme

    Institute of Scientific and Technical Information of China (English)

    李继国; 李建中; 曹珍富; 张亦辰

    2004-01-01

    In 1996, Mambo et al introduced the concept of proxy signature. However, proxy signature can only provide the delegated authenticity and cannot provide confidentiality. Recently, Gamage et al and Chan and Wei proposed different proxy signcryption schemes respectively, which extended the concept of proxy signature.However, only the specified receiver can decrypt and verify the validity of proxy signcryption in their schemes.To protect the receiver' s benefit in case of a later dispute, Wu and Hsu proposed a convertible authenticated encryption scheme, which carn enable the receiver to convert signature into an ordinary one that can be verified by anyone. Based on Wu and Hsu' s scheme and improved Kim' s scheme, we propose a convertible proxy signcryption scheme. The security of the proposed scheme is based on the intractability of reversing the one-way hash function and solving the discrete logarithm problem. The proposed scheme can satisfy all properties of strong proxy signature and withstand the public key substitution attack and does not use secure channel. In addition, the proposed scheme can be extended to convertible threshold proxy signcryption scheme.

  10. Improved HDFS scheme based on erasure code and dynamical-replication system%基于纠删码和动态副本策略的HDFS改进系统

    Institute of Scientific and Technical Information of China (English)

    李晓恺; 代翔; 李文杰; 崔喆

    2012-01-01

    为了让Hadoop分布式文件系统(HDFS)达到更高的存储效率以及更加优化的负载均衡能力,针对HDFS的多副本存储技术提出了改进方案——Noah.Noah引入了编码和译码模块,对HDFS中的block进行编码分解,生成更多数量的数据分片(section),并随机地分散保存到集群当中,替代原有系统的多副本容灾策略;在集群出现节点失效的情况下,通过收集与失效block相关的任意70%左右的section进行原始数据的恢复;同时根据分布式集群运行情况以及对副本数目需求的不同采用动态副本策略.通过相关的集群实验,表明Noah在容灾效率、负载均衡、存储成本以及安全性上对HDFS作了相应的优化.%In order to improve the storage efficiency of Hadoop Distributed File System (HDFS) and its load balance ability, this paper presented an improved solution named Noah to replace the original multiple-replication strategy. Noah introduced a coding module to HDFS. Instead of adopting the multiple-replication strategy by the original system, the module encoded every data block of HDFS into a greater number of data sections (pieces), and saved them dispersedly into the clusters of the storage system in distributed fashion. In the case of cluster failure, the original data would be recovered via decoding by collecting any 70% of the sections, while the dynamic replication strategy also worked synchronously, in which the amount of copies would dynamically change with the demand. The experimental results in analogous clusters of storage system show the feasibility and advantages of new measures in proposed solution.

  11. Vulnerability of MRD-Code-based Universal Secure Network Coding against Stronger Eavesdroppers

    CERN Document Server

    Shioji, Eitaro; Uyematsu, Tomohiko

    2010-01-01

    Silva et al. proposed a universal secure network coding scheme based on MRD codes, which can be applied to any underlying network code. This paper considers a stronger eavesdropping model where the eavesdroppers possess the ability to re-select the tapping links during the transmission. We give a proof for the impossibility of attaining universal security against such adversaries using Silva et al.'s code for all choices of code parameters, even with restricted number of tapped links. We also consider the cases with restricted tapping duration and derive some conditions for this code to be secure.

  12. Difference Schemes and Applications

    Science.gov (United States)

    2015-02-06

    of the shallow water equations that is well suited for complex geometries and moving boundaries. Another (similar) regularization of...the solid wall extrapolation followed by the interpolation in the phase space (by solving the Riemann problem between the internal cell averages and...scheme. This Godunov-type scheme enjoys all major advantages of Riemann -problem-solver-free, non-oscillatory central schemes and, at the same time, have

  13. Efficient Threshold Signature Scheme

    Directory of Open Access Journals (Sweden)

    Sattar J Aboud

    2012-01-01

    Full Text Available In this paper, we introduce a new threshold signature RSA-typed scheme. The proposed scheme has the characteristics of un-forgeable and robustness in random oracle model. Also, signature generation and verification is entirely non-interactive. In addition, the length of the entity signature participate is restricted by a steady times of the length of the RSA signature modulus. Also, the signing process of the proposed scheme is more efficient in terms of time complexity and interaction.

  14. Stateless Transitive Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    MA Chun-guang; CAI Man-chun; YANG Yi-xian

    2004-01-01

    A new practical method is introduced to transform the stateful transitive signature scheme to stateless one without the loss of security. According to the approach, two concrete stateless transitive signature schemes based on Factoring and RSA are presented respectively. Under the assumption of the hardness of factoring and one-more- RSA-inversion problem, both two schemes are secure under the adaptive chosen-message attacks in random oracle model.

  15. Dropout--Mertonian or reproduction scheme?

    Science.gov (United States)

    Horowitz, T R

    1992-01-01

    This article reports on dropouts in four schools in Israel. Two main research questions were addressed: (1) Is it possible to identify a potential dropout through examination of his/her attitudes and competence before the actual act of leaving school? (2) Is there a difference between dropouts and persistent students in different educational settings (academic, vocational, agricultural, and comprehensive high schools)? Significant differences were found in the attitudes of persistent students and dropouts even before the act of dropping out occurred. In the vocational, comprehensive, and agricultural schools, the dropouts scored more positively on the self-estrangement, meaninglessness, and misfeasance scales. In the academic school, the dropouts scored positively on the anxiety scale. Results were interpreted in light of the Mertonian scheme of ends and means as well as the reproduction scheme. The Mertonian scheme was deemed more applicable.

  16. Speech coding

    Energy Technology Data Exchange (ETDEWEB)

    Ravishankar, C., Hughes Network Systems, Germantown, MD

    1998-05-08

    Speech is the predominant means of communication between human beings and since the invention of the telephone by Alexander Graham Bell in 1876, speech services have remained to be the core service in almost all telecommunication systems. Original analog methods of telephony had the disadvantage of speech signal getting corrupted by noise, cross-talk and distortion Long haul transmissions which use repeaters to compensate for the loss in signal strength on transmission links also increase the associated noise and distortion. On the other hand digital transmission is relatively immune to noise, cross-talk and distortion primarily because of the capability to faithfully regenerate digital signal at each repeater purely based on a binary decision. Hence end-to-end performance of the digital link essentially becomes independent of the length and operating frequency bands of the link Hence from a transmission point of view digital transmission has been the preferred approach due to its higher immunity to noise. The need to carry digital speech became extremely important from a service provision point of view as well. Modem requirements have introduced the need for robust, flexible and secure services that can carry a multitude of signal types (such as voice, data and video) without a fundamental change in infrastructure. Such a requirement could not have been easily met without the advent of digital transmission systems, thereby requiring speech to be coded digitally. The term Speech Coding is often referred to techniques that represent or code speech signals either directly as a waveform or as a set of parameters by analyzing the speech signal. In either case, the codes are transmitted to the distant end where speech is reconstructed or synthesized using the received set of codes. A more generic term that is applicable to these techniques that is often interchangeably used with speech coding is the term voice coding. This term is more generic in the sense that the

  17. Generalized Gray Codes for Local Rank Modulation

    CERN Document Server

    Gad, Eyal En; Schwartz, Moshe; Bruck, Jehoshua

    2011-01-01

    We consider the local rank-modulation scheme in which a sliding window going over a sequence of real-valued variables induces a sequence of permutations. Local rank-modulation is a generalization of the rank-modulation scheme, which has been recently suggested as a way of storing information in flash memory. We study Gray codes for the local rank-modulation scheme in order to simulate conventional multi-level flash cells while retaining the benefits of rank modulation. Unlike the limited scope of previous works, we consider code constructions for the entire range of parameters including the code length, sliding window size, and overlap between adjacent windows. We show our constructed codes have asymptotically-optimal rate. We also provide efficient encoding, decoding, and next-state algorithms.

  18. A quantum analog of Huffman coding

    CERN Document Server

    Braunstein, S L; Gottesman, D; Lo, H K; Braunstein, Samuel L.; Fuchs, Christopher A.; Gottesman, Daniel; Lo, Hoi-Kwong

    1998-01-01

    We analyse a generalization of Huffman coding to the quantum case. In particular, we notice various difficulties in using instantaneous codes for quantum communication. However, for the storage of quantum information, we have succeeded in constructing a Huffman-coding inspired quantum scheme. The number of computational steps in the encoding and decoding processes of N quantum signals can be made to be polynomial in log N by a massively parallel implementation of a quantum gate array. This is to be compared with the N^3 computational steps required in the sequential implementation by Cleve and DiVincenzo of the well-known quantum noiseless block coding scheme by Schumacher. The powers and limitations in using this scheme in communication are also discussed.

  19. M-PSK Cooperative Trellis Codes for Coordinate Interleaved Coded Cooperation

    Directory of Open Access Journals (Sweden)

    Özgür Oruç

    2009-01-01

    Full Text Available M-PSK cooperative trellis codes are proposed for two-user coordinate interleaved coded cooperation operating over quasistatic Rayleigh fading channels. The coding approach properly combines cooperative and modulation diversity techniques to take their full advantage. Two selective cooperation schemes are considered related to whether users know the cooperation status or not. Upper bounds on the pairwise error probability of the considered schemes are derived for each cooperation case which lead to new code design criteria. Based on these criteria, 4-, 8-, 16-state QPSK and 8-, 16-state 8PSK cooperative trellis codes are obtained by means of exhaustive computer search. The error performance evaluation of the new codes by computer simulations shows that they outperform the corresponding best space-time codes used in cooperation with coordinate interleaving.

  20. M-PSK Cooperative Trellis Codes for Coordinate Interleaved Coded Cooperation

    Directory of Open Access Journals (Sweden)

    Oruç Özgür

    2009-01-01

    Full Text Available Abstract M-PSK cooperative trellis codes are proposed for two-user coordinate interleaved coded cooperation operating over quasistatic Rayleigh fading channels. The coding approach properly combines cooperative and modulation diversity techniques to take their full advantage. Two selective cooperation schemes are considered related to whether users know the cooperation status or not. Upper bounds on the pairwise error probability of the considered schemes are derived for each cooperation case which lead to new code design criteria. Based on these criteria, 4-, 8-, 16-state QPSK and 8-, 16-state 8PSK cooperative trellis codes are obtained by means of exhaustive computer search. The error performance evaluation of the new codes by computer simulations shows that they outperform the corresponding best space-time codes used in cooperation with coordinate interleaving.

  1. Quantum superdense coding based on hyperentanglement

    Institute of Scientific and Technical Information of China (English)

    Zhao Rui-Tong; Guo Qi; Chen Li; Wang Hong-Fu; Zhang Shou

    2012-01-01

    We present a scheme for quantum superdense coding with hyperentanglement,in which the sender can transfer four bits of classical information by sending only one photon.The important device in the scheme is the hyperentangled Bell-state analyzer in both polarization and frequency degrees of freedom,which is also constructed in the paper by using a quantum nondemolition detector assisted by cross-Kerr nonlinearity.Our scheme can transfer more information with less resources than the existing schemes and is nearly deterministic and nondestructive.

  2. Distributed Arithmetic Coding for the Asymmetric Slepian-Wolf problem

    CERN Document Server

    Grangetto, M; Olmo, G

    2007-01-01

    Distributed source coding schemes are typically based on the use of channels codes as source codes. In this paper we propose a new paradigm, termed "distributed arithmetic coding", which exploits the fact that arithmetic codes are good source as well as channel codes. In particular, we propose a distributed binary arithmetic coder for Slepian-Wolf coding with decoder side information, along with a soft joint decoder. The proposed scheme provides several advantages over existing Slepian-Wolf coders, especially its good performance at small block lengths, and the ability to incorporate arbitrary source models in the encoding process, e.g. context-based statistical models. We have compared the performance of distributed arithmetic coding with turbo codes and low-density parity-check codes, and found that the proposed approach has very competitive performance.

  3. Joint Schemes for Physical Layer Security and Error Correction

    Science.gov (United States)

    Adamo, Oluwayomi

    2011-01-01

    The major challenges facing resource constraint wireless devices are error resilience, security and speed. Three joint schemes are presented in this research which could be broadly divided into error correction based and cipher based. The error correction based ciphers take advantage of the properties of LDPC codes and Nordstrom Robinson code. A…

  4. CodedStream: live media streaming with overlay coded multicast

    Science.gov (United States)

    Guo, Jiang; Zhu, Ying; Li, Baochun

    2003-12-01

    Multicasting is a natural paradigm for streaming live multimedia to multiple end receivers. Since IP multicast is not widely deployed, many application-layer multicast protocols have been proposed. However, all of these schemes focus on the construction of multicast trees, where a relatively small number of links carry the multicast streaming load, while the capacity of most of the other links in the overlay network remain unused. In this paper, we propose CodedStream, a high-bandwidth live media distribution system based on end-system overlay multicast. In CodedStream, we construct a k-redundant multicast graph (a directed acyclic graph) as the multicast topology, on which network coding is applied to work around bottlenecks. Simulation results have shown that the combination of k-redundant multicast graph and network coding may indeed bring significant benefits with respect to improving the quality of live media at the end receivers.

  5. Benchmark studies of BOUT++ code and TPSMBI code on neutral transport during SMBI

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.H. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); University of Science and Technology of China, Hefei 230026 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China); Wang, Z.H., E-mail: zhwang@swip.ac.cn [Southwestern Institute of Physics, Chengdu 610041 (China); Guo, W., E-mail: wfguo@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China); Ren, Q.L. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Sun, A.P.; Xu, M.; Wang, A.K. [Southwestern Institute of Physics, Chengdu 610041 (China); Xiang, N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China)

    2017-06-09

    SMBI (supersonic molecule beam injection) plays an important role in tokamak plasma fuelling, density control and ELM mitigation in magnetic confinement plasma physics, which has been widely used in many tokamaks. The trans-neut module of BOUT++ code is the only large-scale parallel 3D fluid code used to simulate the SMBI fueling process, while the TPSMBI (transport of supersonic molecule beam injection) code is a recent developed 1D fluid code of SMBI. In order to find a method to increase SMBI fueling efficiency in H-mode plasma, especially for ITER, it is significant to first verify the codes. The benchmark study between the trans-neut module of BOUT++ code and the TPSMBI code on radial transport dynamics of neutral during SMBI has been first successfully achieved in both slab and cylindrical coordinates. The simulation results from the trans-neut module of BOUT++ code and TPSMBI code are consistent very well with each other. Different upwind schemes have been compared to deal with the sharp gradient front region during the inward propagation of SMBI for the code stability. The influence of the WENO3 (weighted essentially non-oscillatory) and the third order upwind schemes on the benchmark results has also been discussed. - Highlights: • A 1D model of SMBI has developed. • Benchmarks of BOUT++ and TPSMBI codes have first been finished. • The influence of the WENO3 and the third order upwind schemes on the benchmark results has also been discussed.

  6. Speaking Code

    DEFF Research Database (Denmark)

    Cox, Geoff

    ; alternatives to mainstream development, from performances of the live-coding scene to the organizational forms of commons-based peer production; the democratic promise of social media and their paradoxical role in suppressing political expression; and the market’s emptying out of possibilities for free...... development, Speaking Code unfolds an argument to undermine the distinctions between criticism and practice, and to emphasize the aesthetic and political aspects of software studies. Not reducible to its functional aspects, program code mirrors the instability inherent in the relationship of speech...... expression in the public realm. The book’s line of argument defends language against its invasion by economics, arguing that speech continues to underscore the human condition, however paradoxical this may seem in an era of pervasive computing....

  7. Content layer progressive coding of digital maps

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Jensen, Ole Riis

    2000-01-01

    A new lossless context based method is presented for content progressive coding of limited bits/pixel images, such as maps, company logos, etc., common on the WWW. Progressive encoding is achieved by separating the image into content layers based on other predefined information. Information from...... already coded layers are used when coding subsequent layers. This approach is combined with efficient template based context bi-level coding, context collapsing methods for multi-level images and arithmetic coding. Relative pixel patterns are used to collapse contexts. The number of contexts are analyzed....... The new methods outperform existing coding schemes coding digital maps and in addition provide progressive coding. Compared to the state-of-the-art PWC coder, the compressed size is reduced to 60-70% on our layered test images....

  8. Multiplexed coding in the human basal ganglia

    Science.gov (United States)

    Andres, D. S.; Cerquetti, D.; Merello, M.

    2016-04-01

    A classic controversy in neuroscience is whether information carried by spike trains is encoded by a time averaged measure (e.g. a rate code), or by complex time patterns (i.e. a time code). Here we apply a tool to quantitatively analyze the neural code. We make use of an algorithm based on the calculation of the temporal structure function, which permits to distinguish what scales of a signal are dominated by a complex temporal organization or a randomly generated process. In terms of the neural code, this kind of analysis makes it possible to detect temporal scales at which a time patterns coding scheme or alternatively a rate code are present. Additionally, finding the temporal scale at which the correlation between interspike intervals fades, the length of the basic information unit of the code can be established, and hence the word length of the code can be found. We apply this algorithm to neuronal recordings obtained from the Globus Pallidus pars interna from a human patient with Parkinson’s disease, and show that a time pattern coding and a rate coding scheme co-exist at different temporal scales, offering a new example of multiplexed neuronal coding.

  9. Multiresolution signal decomposition schemes

    NARCIS (Netherlands)

    J. Goutsias (John); H.J.A.M. Heijmans (Henk)

    1998-01-01

    textabstract[PNA-R9810] Interest in multiresolution techniques for signal processing and analysis is increasing steadily. An important instance of such a technique is the so-called pyramid decomposition scheme. This report proposes a general axiomatic pyramid decomposition scheme for signal analysis

  10. Multiresolution signal decomposition schemes

    NARCIS (Netherlands)

    Goutsias, J.; Heijmans, H.J.A.M.

    1998-01-01

    [PNA-R9810] Interest in multiresolution techniques for signal processing and analysis is increasing steadily. An important instance of such a technique is the so-called pyramid decomposition scheme. This report proposes a general axiomatic pyramid decomposition scheme for signal analysis and synthes

  11. Estudio de la Turbulencia a través del Modelo k-épsilon , Mediante un Código Tridimensional con Esquemas de Alto Orden Turbulence Analysis with the k-epsilon Model, Using a Three-Dimensional Code with High Order Schemes

    Directory of Open Access Journals (Sweden)

    L. López-Zamora

    2004-01-01

    Full Text Available Se ha desarrollado un código tridimensional, empleando esquemas de alto orden para evaluar el fenómeno de la turbulencia mediante la implementación del modelo k-épsilon , en una tubería con flujo totalmente desarrollado. La metodología establece la resolución del conjunto de ecuaciones diferenciales usando los esquemas SOU-ULTIMATE y QUICKES-ULTIMATE, a fin de lograr un buen balance entre precisión y aplicabilidad. Los resultados obtenidos con el modelo TURBUL, se compararon contra tres bancos de datos experimentales y contra otras 10 metodologías que emplean el mismo modelo k-épsilon pero ajustado en alguno de sus parámetros. Se concluye que las evaluaciones realizadas sobre la energía cinética turbulenta, la tasa de disipación de energía y la vorticidad a diferentes números de Reynolds han resultado satisfactorias, ofreciendo la ventaja de un menor tiempo computacionalA three dimensional code was developed using high order schemes and the k-epsilon model to evaluate turbulent phenomena in a pipe with fully developed flow. The methodology establishes the solution of a set of differential equations with SOU-ULTIMATE and QUICKES-ULTIMATE schemes, to attain equilibrium between precision and applicability. Results obtained with the TURBUL model, were compared with three experimental data sets and then compared with 10 different methodologies that use the same k-epsilon model but with some of the parameters adjusted. It is concluded that evaluations of turbulent kinetic energy, energy dissipation rate, and eddy viscosity using different Reynolds numbers were adequate, offering the advantages of shorter computational time

  12. Securing mobile code.

    Energy Technology Data Exchange (ETDEWEB)

    Link, Hamilton E.; Schroeppel, Richard Crabtree; Neumann, William Douglas; Campbell, Philip LaRoche; Beaver, Cheryl Lynn; Pierson, Lyndon George; Anderson, William Erik

    2004-10-01

    If software is designed so that the software can issue functions that will move that software from one computing platform to another, then the software is said to be 'mobile'. There are two general areas of security problems associated with mobile code. The 'secure host' problem involves protecting the host from malicious mobile code. The 'secure mobile code' problem, on the other hand, involves protecting the code from malicious hosts. This report focuses on the latter problem. We have found three distinct camps of opinions regarding how to secure mobile code. There are those who believe special distributed hardware is necessary, those who believe special distributed software is necessary, and those who believe neither is necessary. We examine all three camps, with a focus on the third. In the distributed software camp we examine some commonly proposed techniques including Java, D'Agents and Flask. For the specialized hardware camp, we propose a cryptographic technique for 'tamper-proofing' code over a large portion of the software/hardware life cycle by careful modification of current architectures. This method culminates by decrypting/authenticating each instruction within a physically protected CPU, thereby protecting against subversion by malicious code. Our main focus is on the camp that believes that neither specialized software nor hardware is necessary. We concentrate on methods of code obfuscation to render an entire program or a data segment on which a program depends incomprehensible. The hope is to prevent or at least slow down reverse engineering efforts and to prevent goal-oriented attacks on the software and execution. The field of obfuscation is still in a state of development with the central problem being the lack of a basis for evaluating the protection schemes. We give a brief introduction to some of the main ideas in the field, followed by an in depth analysis of a technique called &apos

  13. The moving mesh code Shadowfax

    CERN Document Server

    Vandenbroucke, Bert

    2016-01-01

    We introduce the moving mesh code Shadowfax, which can be used to evolve a mixture of gas, subject to the laws of hydrodynamics and gravity, and any collisionless fluid only subject to gravity, such as cold dark matter or stars. The code is written in C++ and its source code is made available to the scientific community under the GNU Affero General Public License. We outline the algorithm and the design of our implementation, and demonstrate its validity through the results of a set of basic test problems, which are also part of the public version. We also compare Shadowfax with a number of other publicly available codes using different hydrodynamical integration schemes, illustrating the advantages and disadvantages of the moving mesh technique.

  14. The moving mesh code SHADOWFAX

    Science.gov (United States)

    Vandenbroucke, B.; De Rijcke, S.

    2016-07-01

    We introduce the moving mesh code SHADOWFAX, which can be used to evolve a mixture of gas, subject to the laws of hydrodynamics and gravity, and any collisionless fluid only subject to gravity, such as cold dark matter or stars. The code is written in C++ and its source code is made available to the scientific community under the GNU Affero General Public Licence. We outline the algorithm and the design of our implementation, and demonstrate its validity through the results of a set of basic test problems, which are also part of the public version. We also compare SHADOWFAX with a number of other publicly available codes using different hydrodynamical integration schemes, illustrating the advantages and disadvantages of the moving mesh technique.

  15. An Efficient Differential MIMO-OFDM Scheme with Coordinate Interleaving

    Directory of Open Access Journals (Sweden)

    Aksoy Kenan

    2008-01-01

    Full Text Available Abstract We propose a concatenated trellis code (TC and coordinate interleaved differential space-time block code (STBC for OFDM. The coordinate interleaver, provides signal space diversity and improves the codeword error rate (CER performance of the system in wideband channels. Coordinate interleaved differential space-time block codes are proposed and used in the concatenated scheme, TC design criteria are derived, and the CER performances of the proposed system are compared with existing concatenated TC and differential STBC. The comparison showed that the proposed scheme has superior diversity gain and improved CER performance.

  16. An Efficient Differential MIMO-OFDM Scheme with Coordinate Interleaving

    Directory of Open Access Journals (Sweden)

    Kenan Aksoy

    2007-12-01

    Full Text Available We propose a concatenated trellis code (TC and coordinate interleaved differential space-time block code (STBC for OFDM. The coordinate interleaver, provides signal space diversity and improves the codeword error rate (CER performance of the system in wideband channels. Coordinate interleaved differential space-time block codes are proposed and used in the concatenated scheme, TC design criteria are derived, and the CER performances of the proposed system are compared with existing concatenated TC and differential STBC. The comparison showed that the proposed scheme has superior diversity gain and improved CER performance.

  17. The Aster code; Code Aster

    Energy Technology Data Exchange (ETDEWEB)

    Delbecq, J.M

    1999-07-01

    The Aster code is a 2D or 3D finite-element calculation code for structures developed by the R and D direction of Electricite de France (EdF). This dossier presents a complete overview of the characteristics and uses of the Aster code: introduction of version 4; the context of Aster (organisation of the code development, versions, systems and interfaces, development tools, quality assurance, independent validation); static mechanics (linear thermo-elasticity, Euler buckling, cables, Zarka-Casier method); non-linear mechanics (materials behaviour, big deformations, specific loads, unloading and loss of load proportionality indicators, global algorithm, contact and friction); rupture mechanics (G energy restitution level, restitution level in thermo-elasto-plasticity, 3D local energy restitution level, KI and KII stress intensity factors, calculation of limit loads for structures), specific treatments (fatigue, rupture, wear, error estimation); meshes and models (mesh generation, modeling, loads and boundary conditions, links between different modeling processes, resolution of linear systems, display of results etc..); vibration mechanics (modal and harmonic analysis, dynamics with shocks, direct transient dynamics, seismic analysis and aleatory dynamics, non-linear dynamics, dynamical sub-structuring); fluid-structure interactions (internal acoustics, mass, rigidity and damping); linear and non-linear thermal analysis; steels and metal industry (structure transformations); coupled problems (internal chaining, internal thermo-hydro-mechanical coupling, chaining with other codes); products and services. (J.S.)

  18. Continuous-variable quantum network coding for coherent states

    Science.gov (United States)

    Shang, Tao; Li, Ke; Liu, Jian-wei

    2017-04-01

    As far as the spectral characteristic of quantum information is concerned, the existing quantum network coding schemes can be looked on as the discrete-variable quantum network coding schemes. Considering the practical advantage of continuous variables, in this paper, we explore two feasible continuous-variable quantum network coding (CVQNC) schemes. Basic operations and CVQNC schemes are both provided. The first scheme is based on Gaussian cloning and ADD/SUB operators and can transmit two coherent states across with a fidelity of 1/2, while the second scheme utilizes continuous-variable quantum teleportation and can transmit two coherent states perfectly. By encoding classical information on quantum states, quantum network coding schemes can be utilized to transmit classical information. Scheme analysis shows that compared with the discrete-variable paradigms, the proposed CVQNC schemes provide better network throughput from the viewpoint of classical information transmission. By modulating the amplitude and phase quadratures of coherent states with classical characters, the first scheme and the second scheme can transmit 4{log _2}N and 2{log _2}N bits of information by a single network use, respectively.

  19. Optimal codes as Tanner codes with cyclic component codes

    DEFF Research Database (Denmark)

    Høholdt, Tom; Pinero, Fernando; Zeng, Peng

    2014-01-01

    In this article we study a class of graph codes with cyclic code component codes as affine variety codes. Within this class of Tanner codes we find some optimal binary codes. We use a particular subgraph of the point-line incidence plane of A(2,q) as the Tanner graph, and we are able to describe...... the codes succinctly using Gröbner bases....

  20. A Novel Pseudo-code Spread Spectrum Modulation Scheme of Frequency Chirp Binary Offset Garrier and Its Characteristics%基于扫频二进制偏移副载波的伪码扩频调制体制及其特性的研究

    Institute of Scientific and Technical Information of China (English)

    杨宜康; 彭澎; 易国锴; 李雪

    2015-01-01

    In this paper, based on the mathematical model of conventional Binary Offset Carrier (BOC) modulation, a novel pseudo-code spread spectrum modulation scheme of Frequency Chirp Binary Offset Carrier (FC-BOC) is proposed. FC-BOC modulation scheme is constructed by introducing the binary offset carrier of frequency chirp instead of binary offset carrier of fixed frequency in the conventional BOC modulation mathematical model. Therefore, FC-BOC signal has a lot of characteristics inherited from BOC signal and several unique characteristics. Simulation and algorithm experiment show that the FC-BOC modulation scheme retains the primary advantages of BOC modulation, moreover, the FC-BOC signal acquires a narrow and sharp correlation main-peak with extremely suppressed side-peaks for avoiding multiple correlation peak ambiguity naturally, flat power spectral density function similar to band-pass white noise. FC-BOC modulation systems, either signal generating algorithms or signal receiving algorithms, have similar structure and equivalent complexity to conventional BOC modulation.%该文基于常规二进制偏移载波(BOC)调制体制的数学模型,提出一种新型的基于扫频二进制偏移载波调制(FC-BOC)的伪码扩频体制。在这种调制体制中,BOC 调制体制数学模型中的固定频率二进制偏移载波被改进为线性扫频二进制偏移载波,使之不仅继承了BOC信号的性质,还具有更加独特的性质。仿真研究和算法实验表明:FC-BOC调制体制保留了BOC调制体制的主要优点,特别是具有狭窄的主相关峰和出色的副峰抑制特征而避免了多相关峰模糊性,功率谱密度函数呈现类似带通白噪声功率谱密度函数的形态。FC-BOC调制体制信号生成算法、接收算法的结构与常规BOC调制体制类似,算法复杂度相当于常规BOC调制体制,适合纯数字编程设计实现。

  1. Differential modulation based on space-time block codes

    Institute of Scientific and Technical Information of China (English)

    李正权; 胡光锐

    2004-01-01

    A differential modulation scheme using space-time block codes is put forward. Compared with other schemes,our scheme has lower computational complexity and has a simpler decoder. In the case of three or four transmitter antennas, our scheme has a higher rate a higher coding gain and a lower bit error rate for a given rate. Then we made simulations for space-time block codes as well as group codes in the case of two, three, four and five transmit antennas. The simulations prove that using two transmit antennas, one receive antenna and code rate of 4 bits/s/Hz, the differential STBC method outperform the differential group codes method by 4 dB. Useing three, four and five transmit antennas,one receive antenna, and code rate of 3 bits/s/Hz are adopted, the differential STBC method outperform the differential group codes method by 5 dB, 6.5 dB and 7 dB, respectively. In other words, the differential modulation scheme based on space-time block code is better than the corresponding differential modulation scheme

  2. A General Symbolic PDE Solver Generator: Beyond Explicit Schemes

    Directory of Open Access Journals (Sweden)

    K. Sheshadri

    2003-01-01

    Full Text Available This paper presents an extension of our Mathematica- and MathCode-based symbolic-numeric framework for solving a variety of partial differential equation (PDE problems. The main features of our earlier work, which implemented explicit finite-difference schemes, include the ability to handle (1 arbitrary number of dependent variables, (2 arbitrary dimensionality, and (3 arbitrary geometry, as well as (4 developing finite-difference schemes to any desired order of approximation. In the present paper, extensions of this framework to implicit schemes and the method of lines are discussed. While C++ code is generated, using the MathCode system for the implicit method, Modelica code is generated for the method of lines. The latter provides a preliminary PDE support for the Modelica language. Examples illustrating the various aspects of the solver generator are presented.

  3. Coding with partially hidden Markov models

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Rissanen, J.

    1995-01-01

    Partially hidden Markov models (PHMM) are introduced. They are a variation of the hidden Markov models (HMM) combining the power of explicit conditioning on past observations and the power of using hidden states. (P)HMM may be combined with arithmetic coding for lossless data compression. A general...... 2-part coding scheme for given model order but unknown parameters based on PHMM is presented. A forward-backward reestimation of parameters with a redefined backward variable is given for these models and used for estimating the unknown parameters. Proof of convergence of this reestimation is given....... The PHMM structure and the conditions of the convergence proof allows for application of the PHMM to image coding. Relations between the PHMM and hidden Markov models (HMM) are treated. Results of coding bi-level images with the PHMM coding scheme is given. The results indicate that the PHMM can adapt...

  4. Fragment separator momentum compression schemes

    Energy Technology Data Exchange (ETDEWEB)

    Bandura, Laura, E-mail: bandura@anl.gov [Facility for Rare Isotope Beams (FRIB), 1 Cyclotron, East Lansing, MI 48824-1321 (United States); National Superconducting Cyclotron Lab, Michigan State University, 1 Cyclotron, East Lansing, MI 48824-1321 (United States); Erdelyi, Bela [Argonne National Laboratory, Argonne, IL 60439 (United States); Northern Illinois University, DeKalb, IL 60115 (United States); Hausmann, Marc [Facility for Rare Isotope Beams (FRIB), 1 Cyclotron, East Lansing, MI 48824-1321 (United States); Kubo, Toshiyuki [RIKEN Nishina Center, RIKEN, Wako (Japan); Nolen, Jerry [Argonne National Laboratory, Argonne, IL 60439 (United States); Portillo, Mauricio [Facility for Rare Isotope Beams (FRIB), 1 Cyclotron, East Lansing, MI 48824-1321 (United States); Sherrill, Bradley M. [National Superconducting Cyclotron Lab, Michigan State University, 1 Cyclotron, East Lansing, MI 48824-1321 (United States)

    2011-07-21

    We present a scheme to use a fragment separator and profiled energy degraders to transfer longitudinal phase space into transverse phase space while maintaining achromatic beam transport. The first order beam optics theory of the method is presented and the consequent enlargement of the transverse phase space is discussed. An interesting consequence of the technique is that the first order mass resolving power of the system is determined by the first dispersive section up to the energy degrader, independent of whether or not momentum compression is used. The fragment separator at the Facility for Rare Isotope Beams is a specific application of this technique and is described along with simulations by the code COSY INFINITY.

  5. Fragment separator momentum compression schemes.

    Energy Technology Data Exchange (ETDEWEB)

    Bandura, L.; Erdelyi, B.; Hausmann, M.; Kubo, T.; Nolen, J.; Portillo, M.; Sherrill, B.M. (Physics); (MSU); (Northern Illinois Univ.); (RIKEN)

    2011-07-21

    We present a scheme to use a fragment separator and profiled energy degraders to transfer longitudinal phase space into transverse phase space while maintaining achromatic beam transport. The first order beam optics theory of the method is presented and the consequent enlargement of the transverse phase space is discussed. An interesting consequence of the technique is that the first order mass resolving power of the system is determined by the first dispersive section up to the energy degrader, independent of whether or not momentum compression is used. The fragment separator at the Facility for Rare Isotope Beams is a specific application of this technique and is described along with simulations by the code COSY INFINITY.

  6. A Spatial Domain Quantum Watermarking Scheme

    Science.gov (United States)

    Wei, Zhan-Hong; Chen, Xiu-Bo; Xu, Shu-Jiang; Niu, Xin-Xin; Yang, Yi-Xian

    2016-07-01

    This paper presents a spatial domain quantum watermarking scheme. For a quantum watermarking scheme, a feasible quantum circuit is a key to achieve it. This paper gives a feasible quantum circuit for the presented scheme. In order to give the quantum circuit, a new quantum multi-control rotation gate, which can be achieved with quantum basic gates, is designed. With this quantum circuit, our scheme can arbitrarily control the embedding position of watermark images on carrier images with the aid of auxiliary qubits. Besides reversely acting the given quantum circuit, the paper gives another watermark extracting algorithm based on quantum measurements. Moreover, this paper also gives a new quantum image scrambling method and its quantum circuit. Differ from other quantum watermarking schemes, all given quantum circuits can be implemented with basic quantum gates. Moreover, the scheme is a spatial domain watermarking scheme, and is not based on any transform algorithm on quantum images. Meanwhile, it can make sure the watermark be secure even though the watermark has been found. With the given quantum circuit, this paper implements simulation experiments for the presented scheme. The experimental result shows that the scheme does well in the visual quality and the embedding capacity. Supported by the National Natural Science Foundation of China under Grant Nos. 61272514, 61170272, 61373131, 61121061, 61411146001, the program for New Century Excellent Talents under Grant No. NCET-13-0681, the National Development Foundation for Cryptological Research (Grant No. MMJJ201401012) and the Fok Ying Tung Education Foundation under Grant No. 131067, and the Shandong Provincial Natural Science Foundation of China under Grant No. ZR2013FM025

  7. Minimally-sized balanced decomposition schemes for multi-class classification

    NARCIS (Netherlands)

    Smirnov, E.N.; Moed, M.; Nalbantov, G.I.; Sprinkhuizen-Kuyper, I.G.

    2011-01-01

    Error-Correcting Output Coding (ECOC) is a well-known class of decomposition schemes for multi-class classification. It allows representing any multiclass classification problem as a set of binary classification problems. Due to code redundancy ECOC schemes can significantly improve generalization p

  8. A Fuzzy Commitment Scheme

    CERN Document Server

    Al-saggaf, Alawi A

    2008-01-01

    This paper attempt has been made to explain a fuzzy commitment scheme. In the conventional Commitment schemes, both committed string m and valid opening key are required to enable the sender to prove the commitment. However there could be many instances where the transmission involves noise or minor errors arising purely because of the factors over which neither the sender nor the receiver have any control. The fuzzy commitment scheme presented in this paper is to accept the opening key that is close to the original one in suitable distance metric, but not necessarily identical. The concept itself is illustrated with the help of simple situation.

  9. Investigation on the MOC with a linear source approximation scheme in three-dimensional assembly

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Chenglin; Cao, Xinrong [Harbin Engineering University, Haribin (China)

    2014-08-15

    Method of characteristics (MOC) for solving neutron transport equation has already become one of the fundamental methods for lattice calculation of nuclear design code system. At present, MOC has three schemes to deal with the neutron source of the transport equation: the flat source approximation of the step characteristics (SC) scheme, the diamond difference (DD) scheme and the linear source (LS) characteristics scheme. The MOC for SC scheme and DD scheme need large storage space and long computing time when they are used to calculate large-scale three-dimensional neutron transport problems. In this paper, a LS scheme and its correction for negative source distribution were developed and added to DRAGON code. This new scheme was compared with the SC scheme and DD scheme which had been applied in this code. As an open source code, DRAGON could solve three-dimensional assembly with MOC method. Detailed calculation is conducted on two-dimensional VVER-1000 assembly under three schemes of MOC. The numerical results indicate that coarse mesh could be used in the LS scheme with the same accuracy. And the LS scheme applied in DRAGON is effective and expected results are achieved. Then three-dimensional cell problem and VVER-1000 assembly are calculated with LS scheme and SC scheme. The results show that less memory and shorter computational time are employed in LS scheme compared with SC scheme. It is concluded that by using LS scheme, DRAGON is able to calculate large-scale three-dimensional problems with less storage space and shorter computing time.

  10. Testing hydrodynamics schemes in galaxy disc simulations

    Science.gov (United States)

    Few, C. G.; Dobbs, C.; Pettitt, A.; Konstandin, L.

    2016-08-01

    We examine how three fundamentally different numerical hydrodynamics codes follow the evolution of an isothermal galactic disc with an external spiral potential. We compare an adaptive mesh refinement code (RAMSES), a smoothed particle hydrodynamics code (SPHNG), and a volume-discretized mesh-less code (GIZMO). Using standard refinement criteria, we find that RAMSES produces a disc that is less vertically concentrated and does not reach such high densities as the SPHNG or GIZMO runs. The gas surface density in the spiral arms increases at a lower rate for the RAMSES simulations compared to the other codes. There is also a greater degree of substructure in the SPHNG and GIZMO runs and secondary spiral arms are more pronounced. By resolving the Jeans length with a greater number of grid cells, we achieve more similar results to the Lagrangian codes used in this study. Other alterations to the refinement scheme (adding extra levels of refinement and refining based on local density gradients) are less successful in reducing the disparity between RAMSES and SPHNG/GIZMO. Although more similar, SPHNG displays different density distributions and vertical mass profiles to all modes of GIZMO (including the smoothed particle hydrodynamics version). This suggests differences also arise which are not intrinsic to the particular method but rather due to its implementation. The discrepancies between codes (in particular, the densities reached in the spiral arms) could potentially result in differences in the locations and time-scales for gravitational collapse, and therefore impact star formation activity in more complex galaxy disc simulations.

  11. Efficient MIMO-OFDM Schemes for Future Terrestrial Digital TV with Unequal Received Powers

    CERN Document Server

    Nasser, Youssef; Crussière, Matthieu; Pasquero, Oudomsack

    2008-01-01

    This article investigates the effect of equal and unequal received powers on the performances of different MIMO-OFDM schemes for terrestrial digital TV. More precisely, we focus on three types of non-orthogonal schemes: the BLAST scheme, the Linear Dispersion (LD) code and the Golden code, and we compare their performances to that of Alamouti scheme. Using two receiving antennas, we show that for moderate attenuation on the second antenna and high spectral efficiency, Golden code outperforms other schemes. However, Alamouti scheme presents the best performance for low spectral efficiency and equal received powers or when one antenna is dramatically damaged. When three antennas are used, we show that Golden code offers the highest robustness to power unbalance at the receiving side

  12. IPCT: A scheme for mobile authentication

    Directory of Open Access Journals (Sweden)

    Vishnu Shankar

    2016-09-01

    Full Text Available Mobile is becoming a part of everyone's life and as their power of computation and storage is rising and cost is coming down. Most of mobile phone users have a lot of private data which they want to protect from others (La Polla et al., 2013. It means user must be authenticated properly for accessing the mobile resources. Normally user is authenticated using text passwords, PIN, face recognition or patterns etc. All these methods are used but they have some shortcomings. In this paper we have seen various existing methods of mobile authentications and proposed our improved mobile authentication IPCT scheme. We have compared our Image Pass Code with tapping scheme with existing techniques and shown that our scheme is better than existing techniques.

  13. Generalized Distributed Network Coding Based on Nonbinary Linear Block Codes for Multi-User Cooperative Communications

    CERN Document Server

    Rebelatto, João Luiz; Li, Yonghui; Vucetic, Branka

    2010-01-01

    In this work, we propose and analyze a generalized construction of distributed network codes for a network consisting of M users sending different information to a common base station through independent block fading channels. The aim is to increase the diversity order of the system without reducing its code rate. The proposed scheme, called generalized dynamic network codes (GDNC), is a generalization of the dynamic network codes (DNC) recently proposed by Xiao and Skoglung. The design of the network codes that maximizes the diversity order is recognized as equivalent to the design of linear block codes over a nonbinary finite field under the Hamming metric. The proposed scheme offers a much better tradeoff between rate and diversity order. An outage probability analysis showing the improved performance is carried out, and computer simulations results are shown to agree with the analytical results.

  14. Civil Code, 11 December 1987.

    Science.gov (United States)

    1988-01-01

    Article 162 of this Mexican Code provides, among other things, that "Every person has the right freely, responsibly, and in an informed fashion to determine the number and spacing of his or her children." When a marriage is involved, this right is to be observed by the spouses "in agreement with each other." The civil codes of the following states contain the same provisions: 1) Baja California (Art. 159 of the Civil Code of 28 April 1972 as revised in Decree No. 167 of 31 January 1974); 2) Morelos (Art. 255 of the Civil Code of 26 September 1949 as revised in Decree No. 135 of 29 December 1981); 3) Queretaro (Art. 162 of the Civil Code of 29 December 1950 as revised in the Act of 9 January 1981); 4) San Luis Potosi (Art. 147 of the Civil Code of 24 March 1946 as revised in 13 June 1978); Sinaloa (Art. 162 of the Civil Code of 18 June 1940 as revised in Decree No. 28 of 14 October 1975); 5) Tamaulipas (Art. 146 of the Civil Code of 21 November 1960 as revised in Decree No. 20 of 30 April 1975); 6) Veracruz-Llave (Art. 98 of the Civil Code of 1 September 1932 as revised in the Act of 30 December 1975); and 7) Zacatecas (Art. 253 of the Civil Code of 9 February 1965 as revised in Decree No. 104 of 13 August 1975). The Civil Codes of Puebla and Tlaxcala provide for this right only in the context of marriage with the spouses in agreement. See Art. 317 of the Civil Code of Puebla of 15 April 1985 and Article 52 of the Civil Code of Tlaxcala of 31 August 1976 as revised in Decree No. 23 of 2 April 1984. The Family Code of Hidalgo requires as a formality of marriage a certification that the spouses are aware of methods of controlling fertility, responsible parenthood, and family planning. In addition, Article 22 the Civil Code of the Federal District provides that the legal capacity of natural persons is acquired at birth and lost at death; however, from the moment of conception the individual comes under the protection of the law, which is valid with respect to the

  15. Improved FEC Code Based on Concatenated Code for Optical Transmission Systems

    Institute of Scientific and Technical Information of China (English)

    YUAN Jian-guo; JIANG Ze; MAO You-ju

    2006-01-01

    The improved three novel schemes of the super forward error correction(super-FEC) concatenated codes are proposed after the development trend of long-haul optical transmission systems and the defects of the existing FEC codes have been analyzed. The performance simulation of the Reed-Solomon(RS)+Bose-Chaudhuri-Hocguenghem(BCH) inner-outer serial concatenated code is implemented and the conceptions of encoding/decoding the parallel-concatenated code are presented. Furthermore,the simulation results for the RS(255,239)+RS(255,239) code and the RS(255,239)+RS(255,223) code show that the two consecutive concatenated codes are a superior coding scheme with such advantages as the better error correction,moderate redundancy and easy realization compared to the classic RS(255,239) code and other codes,and their signal to noise ratio gains are respectively 2~3 dB more than that of the RS(255,239)code at the bit error rate of 1×10-13. Finally,the frame structure of the novel consecutive concatenated code is arranged to lay a firm foundation in designing its hardware.

  16. Tabled Execution in Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Willcock, J J; Lumsdaine, A; Quinlan, D J

    2008-08-19

    Tabled execution is a generalization of memorization developed by the logic programming community. It not only saves results from tabled predicates, but also stores the set of currently active calls to them; tabled execution can thus provide meaningful semantics for programs that seemingly contain infinite recursions with the same arguments. In logic programming, tabled execution is used for many purposes, both for improving the efficiency of programs, and making tasks simpler and more direct to express than with normal logic programs. However, tabled execution is only infrequently applied in mainstream functional languages such as Scheme. We demonstrate an elegant implementation of tabled execution in Scheme, using a mix of continuation-passing style and mutable data. We also show the use of tabled execution in Scheme for a problem in formal language and automata theory, demonstrating that tabled execution can be a valuable tool for Scheme users.

  17. Homogenous Chaotic Network Serving as a Rate/Population Code to Temporal Code Converter

    Directory of Open Access Journals (Sweden)

    Mikhail V. Kiselev

    2014-01-01

    Full Text Available At present, it is obvious that different sections of nervous system utilize different methods for information coding. Primary afferent signals in most cases are represented in form of spike trains using a combination of rate coding and population coding while there are clear evidences that temporal coding is used in various regions of cortex. In the present paper, it is shown that conversion between these two coding schemes can be performed under certain conditions by a homogenous chaotic neural network. Interestingly, this effect can be achieved without network training and synaptic plasticity.

  18. A concatenated coding scheme for biometric template protection

    NARCIS (Netherlands)

    Shao, Xiaoying; Xu, Haiyun; Veldhuis, Raymond N.J.; Slump, Cornelis H.

    2012-01-01

    Cryptography may mitigate the privacy problem in biometric recognition systems. However, cryptography technologies lack error-tolerance and biometric samples cannot be reproduced exactly, rising the robustness problem. The biometric template protection system needs a good feature extraction algorith

  19. Coded Schemes for Asymmetric Wireless Interfaces: Theory and Practice

    DEFF Research Database (Denmark)

    Moreira, Andre; Lucani Rötter, Daniel Enrique

    2014-01-01

    system with full duplex interfaces. Our second goal is to understand the practical implications of these results by designing a protocol for file transmissions, implement it in Android smart phones, and measure its performance when combining various interfaces, including, Bluetooth, WiFi, and 3G cellular...

  20. Coding theory and cryptography the essentials

    CERN Document Server

    Hankerson, DC; Leonard, DA; Phelps, KT; Rodger, CA; Wall, JR; Wall, J R

    2000-01-01

    Containing data on number theory, encryption schemes, and cyclic codes, this highly successful textbook, proven by the authors in a popular two-quarter course, presents coding theory, construction, encoding, and decoding of specific code families in an ""easy-to-use"" manner appropriate for students with only a basic background in mathematics offering revised and updated material on the Berlekamp-Massey decoding algorithm and convolutional codes. Introducing the mathematics as it is needed and providing exercises with solutions, this edition includes an extensive section on cryptography, desig

  1. Error Robust H.264 Video Transmission Schemes Based on Multi-frame

    Institute of Scientific and Technical Information of China (English)

    余红斌; 余松煜; 王慈

    2004-01-01

    Multi-frame coding is supported by the emerging H. 264. It is important for the enhancement of both coding efficiency and error robustness. In this paper, error resilient schemes for H. 264 based on multi-frame were investigated. Error robust H. 264 video transmission schemes were introduced for the applications with and without a feedback channel. The experimental results demonstrate the effectiveness of the proposed schemes.

  2. 78 FR 46256 - Privacy Act

    Science.gov (United States)

    2013-07-31

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ELECTION COMMISSION 11 CFR Part 1 Privacy Act CFR Correction In Title 11 of the Code of Federal Regulations, revised as of January 1, 2012, on page 5, in Sec. 1.2, the words ``95 and 96 of the Internal Revenue Code of...

  3. Context adaptive coding of bi-level images

    DEFF Research Database (Denmark)

    Forchhammer, Søren

    2008-01-01

    With the advent of sequential arithmetic coding, the focus of highly efficient lossless data compression is placed on modelling the data. Rissanen's Algorithm Context provided an elegant solution to universal coding with optimal convergence rate. Context based arithmetic coding laid the grounds.......g. in the lossless JBIG bi-level image coding standard, and in the entropy coding of contemporary lossless and lossy image and video coding standards and schemes. The theoretical work and analysis of universal context based coding has addressed sequences of data and finite memory models as Markov chains and sources...

  4. Quantitative information measurement and application for machine component classification codes

    Institute of Scientific and Technical Information of China (English)

    LI Ling-Feng; TAN Jian-rong; LIU Bo

    2005-01-01

    Information embodied in machine component classification codes has internal relation with the probability distribution of the code symbol. This paper presents a model considering codes as information source based on Shannon's information theory. Using information entropy, it preserves the mathematical form and quantitatively measures the information amount of a symbol and a bit in the machine component classification coding system. It also gets the maximum value of information amount and the corresponding coding scheme when the category of symbols is fixed. Samples are given to show how to evaluate the information amount of component codes and how to optimize a coding system.

  5. Performance of a space-time block coded code division multiple access system over Nakagami-m fading channels

    Science.gov (United States)

    Yu, Xiangbin; Dong, Tao; Xu, Dazhuan; Bi, Guangguo

    2010-09-01

    By introducing an orthogonal space-time coding scheme, multiuser code division multiple access (CDMA) systems with different space time codes are given, and corresponding system performance is investigated over a Nakagami-m fading channel. A low-complexity multiuser receiver scheme is developed for space-time block coded CDMA (STBC-CDMA) systems. The scheme can make full use of the complex orthogonality of space-time block coding to simplify the high decoding complexity of the existing scheme. Compared to the existing scheme with exponential decoding complexity, it has linear decoding complexity. Based on the performance analysis and mathematical calculation, the average bit error rate (BER) of the system is derived in detail for integer m and non-integer m, respectively. As a result, a tight closed-form BER expression is obtained for STBC-CDMA with an orthogonal spreading code, and an approximate closed-form BER expression is attained for STBC-CDMA with a quasi-orthogonal spreading code. Simulation results show that the proposed scheme can achieve almost the same performance as the existing scheme with low complexity. Moreover, the simulation results for average BER are consistent with the theoretical analysis.

  6. Privacy Act

    Science.gov (United States)

    Learn about the Privacy Act of 1974, the Electronic Government Act of 2002, the Federal Information Security Management Act, and other information about the Environmental Protection Agency maintains its records.

  7. XTR-Kurosawa-Desmedt Scheme

    Institute of Scientific and Technical Information of China (English)

    DING XIU-HUAN; FU ZHI-GUO; ZHANG SHU-GONG

    2009-01-01

    This paper proposes an XTR version of the Kurosawa-Desmedt scheme. Our scheme is secure against adaptive choeen-ciphertext attack under the XTR version of the Decisional Diffie-Hellman assumption in the standard model. Comparing efficiency between the Kurosawa-Desmedt scheme and the proposed XTR-Kurosawa-Desmedt scheme, we find that the proposed scheme is more efficient than the Kurosawa-Desmedt scheme both in communication and computation without compromising security.

  8. NOVEL BIPHASE CODE -INTEGRATED SIDELOBE SUPPRESSION CODE

    Institute of Scientific and Technical Information of China (English)

    Wang Feixue; Ou Gang; Zhuang Zhaowen

    2004-01-01

    A kind of novel binary phase code named sidelobe suppression code is proposed in this paper. It is defined to be the code whose corresponding optimal sidelobe suppression filter outputs the minimum sidelobes. It is shown that there do exist sidelobe suppression codes better than the conventional optimal codes-Barker codes. For example, the sidelobe suppression code of length 11 with filter of length 39 has better sidelobe level up to 17dB than that of Barker code with the same code length and filter length.

  9. From concatenated codes to graph codes

    DEFF Research Database (Denmark)

    Justesen, Jørn; Høholdt, Tom

    2004-01-01

    We consider codes based on simple bipartite expander graphs. These codes may be seen as the first step leading from product type concatenated codes to more complex graph codes. We emphasize constructions of specific codes of realistic lengths, and study the details of decoding by message passing...

  10. Coding of object location in the vibrissal thalamocortical system.

    Science.gov (United States)

    Yu, Chunxiu; Horev, Guy; Rubin, Naama; Derdikman, Dori; Haidarliu, Sebastian; Ahissar, Ehud

    2015-03-01

    In whisking rodents, object location is encoded at the receptor level by a combination of motor and sensory related signals. Recoding of the encoded signals can result in various forms of internal representations. Here, we examined the coding schemes occurring at the first forebrain level that receives inputs necessary for generating such internal representations--the thalamocortical network. Single units were recorded in 8 thalamic and cortical stations in artificially whisking anesthetized rats. Neuronal representations of object location generated across these stations and expressed in response latency and magnitude were classified based on graded and binary coding schemes. Both graded and binary coding schemes occurred across the entire thalamocortical network, with a general tendency of graded-to-binary transformation from thalamus to cortex. Overall, 63% of the neurons of the thalamocortical network coded object position in their firing. Thalamocortical responses exhibited a slow dynamics during which the amount of coded information increased across 4-5 whisking cycles and then stabilized. Taken together, the results indicate that the thalamocortical network contains dynamic mechanisms that can converge over time on multiple coding schemes of object location, schemes which essentially transform temporal coding to rate coding and gradual to labeled-line coding.

  11. Spread-spectrum communication using binary spatiotemporal chaotic codes

    Science.gov (United States)

    Wang, Xingang; Zhan, Meng; Gong, Xiaofeng; Lai, Choy Heng; Lai, Ying-Cheng

    2005-01-01

    We propose a scheme to generate binary code for baseband spread-spectrum communication by using a chain of coupled chaotic maps. We compare the performances of this type of spatiotemporal chaotic code with those of a conventional code used frequently in digital communication, the Gold code, and demonstrate that our code is comparable or even superior to the Gold code in several key aspects: security, bit error rate, code generation speed, and the number of possible code sequences. As the field of communicating with chaos faces doubts in terms of performance comparison with conventional digital communication schemes, our work gives a clear message that communicating with chaos can be advantageous and it deserves further attention from the nonlinear science community.

  12. Succesful labelling schemes

    DEFF Research Database (Denmark)

    Juhl, Hans Jørn; Stacey, Julia

    2001-01-01

    It is usual practice to evaluate the success of a labelling scheme by looking at the awareness percentage, but in many cases this is not sufficient. The awareness percentage gives no indication of which of the consumer segments that are aware of and use labelling schemes and which do not. In the ......It is usual practice to evaluate the success of a labelling scheme by looking at the awareness percentage, but in many cases this is not sufficient. The awareness percentage gives no indication of which of the consumer segments that are aware of and use labelling schemes and which do not....... In the spring of 2001 MAPP carried out an extensive consumer study with special emphasis on the Nordic environmentally friendly label 'the swan'. The purpose was to find out how much consumers actually know and use various labelling schemes. 869 households were contacted and asked to fill in a questionnaire...... it into consideration when I go shopping. The respondent was asked to pick the most suitable answer, which described her use of each label. 29% - also called 'the labelling blind' - responded that they basically only knew the recycling label and the Government controlled organic label 'Ø-mærket'. Another segment of 6...

  13. Multiple descriptions based wavelet image coding

    Institute of Scientific and Technical Information of China (English)

    陈海林; 杨宇航

    2004-01-01

    We present a simple and efficient scheme that combines multiple descriptions coding with wavelet transform under JPEG2000 image coding architecture. To reduce packet losses, controlled amounts of redundancy are added to the wavelet transform coefficients to produce multiple descriptions of wavelet coefficients during the compression process to produce multiple descriptions bit-stream of a compressed image. Even if areceiver gets only parts of descriptions (other descriptions being lost), it can still reconstruct image with acceptable quality. Specifically, the scheme uses not only high-performance wavelet transform to improve compression efficiency, but also multiple descriptions technique to enhance the robustness of the compressed image that is transmitted through unreliable network channels.

  14. Classical codes for quantum broadcast channels

    CERN Document Server

    Savov, Ivan

    2011-01-01

    We discuss two techniques for transmitting classical information over quantum broadcast channels. The first technique is a quantum generalization of the superposition coding scheme for the classical broadcast channel. We use a quantum simultaneous nonunique decoder and obtain a simpler proof of the rate region recently published by Yard et al. in independent work. Our second result is a quantum Marton coding scheme, which gives the best known achievable rate region for quantum broadcast channels. Both results exploit recent advances in quantum simultaneous decoding developed in the context of quantum interference channels.

  15. Context adaptive coding of bi-level images

    DEFF Research Database (Denmark)

    Forchhammer, Søren

    2008-01-01

    With the advent of sequential arithmetic coding, the focus of highly efficient lossless data compression is placed on modelling the data. Rissanen's Algorithm Context provided an elegant solution to universal coding with optimal convergence rate. Context based arithmetic coding laid the grounds...... for the modern paradigm of data compression based on a modelling and a coding stage. One advantage of contexts is their flexibility, e.g. choosing a two-dimensional ("-D) context facilitates efficient image coding. The area of image coding has greatly been influenced by context adaptive coding, applied e.......g. in the lossless JBIG bi-level image coding standard, and in the entropy coding of contemporary lossless and lossy image and video coding standards and schemes. The theoretical work and analysis of universal context based coding has addressed sequences of data and finite memory models as Markov chains and sources...

  16. Testing Hydrodynamics Schemes in Galaxy Disc Simulations

    CERN Document Server

    Few, C G; Pettitt, A; Konstandin, L

    2016-01-01

    We examine how three fundamentally different numerical hydrodynamics codes follow the evolution of an isothermal galactic disc with an external spiral potential. We compare an adaptive mesh refinement code (RAMSES), a smoothed particle hydrodynamics code (sphNG), and a volume-discretised meshless code (GIZMO). Using standard refinement criteria, we find that RAMSES produces a disc that is less vertically concentrated and does not reach such high densities as the sphNG or GIZMO runs. The gas surface density in the spiral arms increases at a lower rate for the RAMSES simulations compared to the other codes. There is also a greater degree of substructure in the sphNG and GIZMO runs and secondary spiral arms are more pronounced. By resolving the Jeans' length with a greater number of grid cells we achieve more similar results to the Lagrangian codes used in this study. Other alterations to the refinement scheme (adding extra levels of refinement and refining based on local density gradients) are less successful i...

  17. Scalable hologram video coding for adaptive transmitting service.

    Science.gov (United States)

    Seo, Young-Ho; Lee, Yoon-Hyuk; Yoo, Ji-Sang; Kim, Dong-Wook

    2013-01-01

    This paper discusses processing techniques for an adaptive digital holographic video service in various reconstruction environments, and proposes two new scalable coding schemes. The proposed schemes are constructed according to the hologram generation or acquisition schemes: hologram-based resolution-scalable coding (HRS) and light source-based signal-to-noise ratio scalable coding (LSS). HRS is applied for holograms that are already acquired or generated, while LSS is applied to the light sources before generating digital holograms. In the LSS scheme, the light source information is lossless coded because it is too important to lose, while the HRS scheme adopts a lossy coding method. In an experiment, we provide eight stages of an HRS scheme whose data compression ratios range from 1:1 to 100:1 for each layered data. For LSS, four layers and 16 layers of scalable coding schemes are provided. We experimentally show that the proposed techniques make it possible to service a digital hologram video adaptively to the various displays with different resolutions, computation capabilities of the receiver side, or bandwidths of the network.

  18. Compact Spreader Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Placidi, M.; Jung, J. -Y.; Ratti, A.; Sun, C.

    2014-07-25

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  19. Towards Symbolic Encryption Schemes

    DEFF Research Database (Denmark)

    Ahmed, Naveed; Jensen, Christian D.; Zenner, Erik

    2012-01-01

    Symbolic encryption, in the style of Dolev-Yao models, is ubiquitous in formal security models. In its common use, encryption on a whole message is specified as a single monolithic block. From a cryptographic perspective, however, this may require a resource-intensive cryptographic algorithm......, namely an authenticated encryption scheme that is secure under chosen ciphertext attack. Therefore, many reasonable encryption schemes, such as AES in the CBC or CFB mode, are not among the implementation options. In this paper, we report new attacks on CBC and CFB based implementations of the well......-known Needham-Schroeder and Denning-Sacco protocols. To avoid such problems, we advocate the use of refined notions of symbolic encryption that have natural correspondence to standard cryptographic encryption schemes....

  20. A cybernetic approach to the origin of the genetic coding mechanism. II. Formation of the code series.

    Science.gov (United States)

    Batchinsky, A G; Ratner, V A

    1976-08-01

    The sequential fulfillment of the principle of succession necessarily guides the main steps of the genetic code evolution to be reflected in its structure. The general scheme of the code series formation is proposed basing on the idea of "group coding" (Woese, 1970). The genetic code supposedly evolved by means of successive divergence of pra-ARS's loci, accompanied by increasing specification of recognition capacity of amino acids and triplets. The sense of codons had not been changed on any step of stochastic code evolution. The formulated rules for code series formation produce a code version, similar to the contemporary one. Based on these rules the scheme of pra-ARS's divergence is proposed resulting in the grouping of amino acids by their polarity and size. Later steps in the evolution of the genetic code were probably based on more detailed features of the amino acids (for example, on their functional similarities like their interchangeabilities in isofunctional proteins).

  1. Good Codes From Generalised Algebraic Geometry Codes

    CERN Document Server

    Jibril, Mubarak; Ahmed, Mohammed Zaki; Tjhai, Cen

    2010-01-01

    Algebraic geometry codes or Goppa codes are defined with places of degree one. In constructing generalised algebraic geometry codes places of higher degree are used. In this paper we present 41 new codes over GF(16) which improve on the best known codes of the same length and rate. The construction method uses places of small degree with a technique originally published over 10 years ago for the construction of generalised algebraic geometry codes.

  2. Security Embedding Codes

    CERN Document Server

    Ly, Hung D; Blankenship, Yufei

    2011-01-01

    This paper considers the problem of simultaneously communicating two messages, a high-security message and a low-security message, to a legitimate receiver, referred to as the security embedding problem. An information-theoretic formulation of the problem is presented. A coding scheme that combines rate splitting, superposition coding, nested binning and channel prefixing is considered and is shown to achieve the secrecy capacity region of the channel in several scenarios. Specifying these results to both scalar and independent parallel Gaussian channels (under an average individual per-subchannel power constraint), it is shown that the high-security message can be embedded into the low-security message at full rate (as if the low-security message does not exist) without incurring any loss on the overall rate of communication (as if both messages are low-security messages). Extensions to the wiretap channel II setting of Ozarow and Wyner are also considered, where it is shown that "perfect" security embedding...

  3. Labeling Schemes with Queries

    OpenAIRE

    2006-01-01

    We study the question of ``how robust are the known lower bounds of labeling schemes when one increases the number of consulted labels''. Let $f$ be a function on pairs of vertices. An $f$-labeling scheme for a family of graphs $\\cF$ labels the vertices of all graphs in $\\cF$ such that for every graph $G\\in\\cF$ and every two vertices $u,v\\in G$, the value $f(u,v)$ can be inferred by merely inspecting the labels of $u$ and $v$. This paper introduces a natural generalization: the notion of $f$-...

  4. A Multidimensional Code For Isothermal Magnetohydrodynamic Flows

    CERN Document Server

    Kim, J; Jones, T W; Hong, S S; Kim, Jongsoo; Ryu, Dongsu

    1999-01-01

    We present a multi-dimensional numerical code to solve isothermal magnetohydrodynamic (IMHD) equations for use in modeling astrophysical flows. First, we have built a one-dimensional code which is based on an explicit finite-difference method on an Eulerian grid, called the total variation diminishing (TVD) scheme. Recipes for building the one-dimensional IMHD code, including the normalized right and left eigenvectors of the IMHD Jacobian matrix, are presented. Then, we have extended the one-dimensional code to a multi-dimensional IMHD code through a Strang-type dimensional splitting. In the multi-dimensional code, an explicit cleaning step has been included to eliminate non-zero $\

  5. Arbitrated quantum signature scheme based on cluster states

    Science.gov (United States)

    Yang, Yu-Guang; Lei, He; Liu, Zhi-Chao; Zhou, Yi-Hua; Shi, Wei-Min

    2016-06-01

    Cluster states can be exploited for some tasks such as topological one-way computation, quantum error correction, teleportation and dense coding. In this paper, we investigate and propose an arbitrated quantum signature scheme with cluster states. The cluster states are used for quantum key distribution and quantum signature. The proposed scheme can achieve an efficiency of 100 %. Finally, we also discuss its security against various attacks.

  6. Benchmark studies of BOUT++ code and TPSMBI code on neutral transport during SMBI

    Science.gov (United States)

    Wang, Y. H.; Wang, Z. H.; Guo, W.; Ren, Q. L.; Sun, A. P.; Xu, M.; Wang, A. K.; Xiang, N.

    2017-06-01

    SMBI (supersonic molecule beam injection) plays an important role in tokamak plasma fuelling, density control and ELM mitigation in magnetic confinement plasma physics, which has been widely used in many tokamaks. The trans_neut module of BOUT++ code is the only large-scale parallel 3D fluid code used to simulate the SMBI fueling process, while the TPSMBI (transport of supersonic molecule beam injection) code is a recent developed 1D fluid code of SMBI. In order to find a method to increase SMBI fueling efficiency in H-mode plasma, especially for ITER, it is significant to first verify the codes. The benchmark study between the trans_neut module of BOUT++ code and the TPSMBI code on radial transport dynamics of neutral during SMBI has been first successfully achieved in both slab and cylindrical coordinates. The simulation results from the trans_neut module of BOUT++ code and TPSMBI code are consistent very well with each other. Different upwind schemes have been compared to deal with the sharp gradient front region during the inward propagation of SMBI for the code stability. The influence of the WENO3 (weighted essentially non-oscillatory) and the third order upwind schemes on the benchmark results has also been discussed.

  7. Alternative health insurance schemes

    DEFF Research Database (Denmark)

    Keiding, Hans; Hansen, Bodil O.

    2002-01-01

    In this paper, we present a simple model of health insurance with asymmetric information, where we compare two alternative ways of organizing the insurance market. Either as a competitive insurance market, where some risks remain uninsured, or as a compulsory scheme, where however, the level...... competitive insurance; this situation turns out to be at least as good as either of the alternatives...

  8. Unequal error control scheme for dimmable visible light communication systems

    Science.gov (United States)

    Deng, Keyan; Yuan, Lei; Wan, Yi; Li, Huaan

    2017-01-01

    Visible light communication (VLC), which has the advantages of a very large bandwidth, high security, and freedom from license-related restrictions and electromagnetic-interference, has attracted much interest. Because a VLC system simultaneously performs illumination and communication functions, dimming control, efficiency, and reliable transmission are significant and challenging issues of such systems. In this paper, we propose a novel unequal error control (UEC) scheme in which expanding window fountain (EWF) codes in an on-off keying (OOK)-based VLC system are used to support different dimming target values. To evaluate the performance of the scheme for various dimming target values, we apply it to H.264 scalable video coding bitstreams in a VLC system. The results of the simulations that are performed using additive white Gaussian noises (AWGNs) with different signal-to-noise ratios (SNRs) are used to compare the performance of the proposed scheme for various dimming target values. It is found that the proposed UEC scheme enables earlier base layer recovery compared to the use of the equal error control (EEC) scheme for different dimming target values and therefore afford robust transmission for scalable video multicast over optical wireless channels. This is because of the unequal error protection (UEP) and unequal recovery time (URT) of the EWF code in the proposed scheme.

  9. A new hydrodynamics code for Type Ia Supernovae

    CERN Document Server

    Leung, S -C; Lin, L -M

    2015-01-01

    A two-dimensional hydrodynamics code for Type Ia supernovae (SNIa) simulations is presented. The code includes a fifth-order shock-capturing scheme WENO, detailed nuclear reaction network, flame-capturing scheme and sub-grid turbulence. For post-processing we have developed a tracer particle scheme to record the thermodynamical history of the fluid elements. We also present a one-dimensional radiative transfer code for computing observational signals. The code solves the Lagrangian hydrodynamics and moment-integrated radiative transfer equations. A local ionization scheme and composition dependent opacity are included. Various verification tests are presented, including standard benchmark tests in one and two dimensions. SNIa models using the pure turbulent deflagration model and the delayed-detonation transition model are studied. The results are consistent with those in the literature. We compute the detailed chemical evolution using the tracer particles' histories, and we construct corresponding bolometric...

  10. Complete multiple round quantum dense coding with quantum logical network

    Institute of Scientific and Technical Information of China (English)

    LI ChunYan; LI XiHan; DENG FuGuo; ZHOU Ping; ZHOU HongYu

    2007-01-01

    We present a complete multiple round quantum dense coding scheme for improving the source capacity of that introduced recently by Zhang et al. The receiver resorts to two qubits for storing the four local unitary operations in each round.

  11. Experimental proposal of probabilistic superdense coding with linear optical elements

    Energy Technology Data Exchange (ETDEWEB)

    Lin Qing; Li Jian; Guo Guangcan [Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026 (China)

    2006-09-14

    In this paper, we propose an experimental scheme of probabilistic superdense coding assisted with linear optical manipulations, photon entanglement produced from parametric down-conversion and postselection from coincidence measurements. The proposal is feasible by current experimental technology.

  12. PERFORMANCE EVALUATION OF LOW DENSITY PARITY CHECK CODES FOR DIGITAL RADIO MONDIALE (DRM) SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In Digital Radio Mondiale (DRM) system, achieving good audio quality becomes a challenge due to its limited band-width of 9 or 10kHz and the very bad fading channels. Therefore, DRM needs highly efficient channel coding schemes. This paper, proposes the schemes which use the Low-Density Parity-Check (LDPC) coded Bit-Interleaved Coded Modulation (BICM) schemes for the implementation of DRM systems.Simulation results show that the proposed system is more efficient than the Rate Compatible Punctured Convolutional (RCPC) coded DRM system on various broadcast channels, and may be recommended as a coding technology for Digital Amplitude Modulation Broadcasting (DAMB) systems of China.

  13. Multi-User Cooperative Diversity through Network Coding Based on Classical Coding Theory

    CERN Document Server

    Rebelatto, João Luiz; Li, Yonghui; Vucetic, Branka

    2010-01-01

    In this work, we propose and analyze a generalized construction of distributed network codes for a network consisting of M users sending different information to a common base station through independent block fading channels. The aim is to increase the diversity order of the system without reducing its code rate. The proposed scheme, called generalized dynamic-network codes (GDNC), is a generalization of the dynamic-network codes (DNC) recently proposed by Xiao and Skoglund. The design of the network codes that maximize the diversity order is recognized as equivalent to the design of linear block codes over a nonbinary finite field under the Hamming metric. We prove that adopting a systematic generator matrix of a maximum distance separable block code over a sufficiently large finite field as the network transfer matrix is a sufficient condition for full diversity order under link failure model. The proposed generalization offers a much better tradeoff between rate and diversity order compared to the DNC. An...

  14. Space Time Codes from Permutation Codes

    CERN Document Server

    Henkel, Oliver

    2006-01-01

    A new class of space time codes with high performance is presented. The code design utilizes tailor-made permutation codes, which are known to have large minimal distances as spherical codes. A geometric connection between spherical and space time codes has been used to translate them into the final space time codes. Simulations demonstrate that the performance increases with the block lengths, a result that has been conjectured already in previous work. Further, the connection to permutation codes allows for moderate complex en-/decoding algorithms.

  15. Analysis of quantum error-correcting codes: Symplectic lattice codes and toric codes

    Science.gov (United States)

    Harrington, James William

    a local classical processing scheme for correcting errors on toric codes, which demonstrates that quantum information can be maintained in two dimensions by purely local (quantum and classical) resources.

  16. ACTS 2014

    DEFF Research Database (Denmark)

    Co-curator of ACTS 2014 together with Rasmus Holmboe, Judith Schwarzbart and Sanne Kofoed. ACTS is the Museum of Contemporary Art’s international bi-annual festival. ACTS was established in 2011 and, while the primary focus is on sound and performance art, it also looks toward socially oriented art...... various possibilities and public spaces as a stage. ACTS takes place in and around the museum and diverse locations in Roskilde city. ACTS is partly curated by the museum staff and partly by guest curators. ACTS 2014 is supported by Nordea-fonden and is a part of the project The Museum goes downtown....

  17. Fundamentals of convolutional coding

    CERN Document Server

    Johannesson, Rolf

    2015-01-01

    Fundamentals of Convolutional Coding, Second Edition, regarded as a bible of convolutional coding brings you a clear and comprehensive discussion of the basic principles of this field * Two new chapters on low-density parity-check (LDPC) convolutional codes and iterative coding * Viterbi, BCJR, BEAST, list, and sequential decoding of convolutional codes * Distance properties of convolutional codes * Includes a downloadable solutions manual

  18. Coded Adaptive Linear Precoded Discrete Multitone Over PLC Channel

    CERN Document Server

    Muhammad, Fahad Syed; Hélard, Jean-François; Crussière, Matthieu

    2008-01-01

    Discrete multitone modulation (DMT) systems exploit the capabilities of orthogonal subcarriers to cope efficiently with narrowband interference, high frequency attenuations and multipath fadings with the help of simple equalization filters. Adaptive linear precoded discrete multitone (LP-DMT) system is based on classical DMT, combined with a linear precoding component. In this paper, we investigate the bit and energy allocation algorithm of an adaptive LP-DMT system taking into account the channel coding scheme. A coded adaptive LPDMT system is presented in the power line communication (PLC) context with a loading algorithm which accommodates the channel coding gains in bit and energy calculations. The performance of a concatenated channel coding scheme, consisting of an inner Wei's 4-dimensional 16-states trellis code and an outer Reed-Solomon code, in combination with the proposed algorithm is analyzed. Theoretical coding gains are derived and simulation results are presented for a fixed target bit error ra...

  19. Adaptive transmission schemes for MISO spectrum sharing systems

    KAUST Repository

    Bouida, Zied

    2013-06-01

    We propose three adaptive transmission techniques aiming to maximize the capacity of a multiple-input-single-output (MISO) secondary system under the scenario of an underlay cognitive radio network. In the first scheme, namely the best antenna selection (BAS) scheme, the antenna maximizing the capacity of the secondary link is used for transmission. We then propose an orthogonal space time bloc code (OSTBC) transmission scheme using the Alamouti scheme with transmit antenna selection (TAS), namely the TAS/STBC scheme. The performance improvement offered by this scheme comes at the expense of an increased complexity and delay when compared to the BAS scheme. As a compromise between these schemes, we propose a hybrid scheme using BAS when only one antenna verifies the interference condition and TAS/STBC when two or more antennas are illegible for communication. We first derive closed-form expressions of the statistics of the received signal-to-interference-and-noise ratio (SINR) at the secondary receiver (SR). These results are then used to analyze the performance of the proposed techniques in terms of the average spectral efficiency, the average number of transmit antennas, and the average bit error rate (BER). This performance is then illustrated via selected numerical examples. © 2013 IEEE.

  20. Recent advances in coding theory for near error-free communications

    Science.gov (United States)

    Cheung, K.-M.; Deutsch, L. J.; Dolinar, S. J.; Mceliece, R. J.; Pollara, F.; Shahshahani, M.; Swanson, L.

    1991-01-01

    Channel and source coding theories are discussed. The following subject areas are covered: large constraint length convolutional codes (the Galileo code); decoder design (the big Viterbi decoder); Voyager's and Galileo's data compression scheme; current research in data compression for images; neural networks for soft decoding; neural networks for source decoding; finite-state codes; and fractals for data compression.

  1. WAVELET-BASED FINE GRANULARITY SCALABLE VIDEO CODING

    Institute of Scientific and Technical Information of China (English)

    ZhangJiangshan; ZhuGuangxi

    2003-01-01

    This letter proposes an efficient wavelet-based fine Granularity Scalable(FGS)coding scheme,where the base layer is encoded with a newly designed wavelet-based coder,and the entancement layer is encoded with Progressive Fins Granularity Scalable(PFGS)coding.This algorithm involves multi-frame motion compensationk,rate-distortion optimizing strategy with Lagrangian cost function and context-based adaptive arithmetic coding.In order to improve efficiency of the enhancenent layer coding,an improved motion estimation scheme that uses both information from the base layer and the enhancement layer is also proposed in this letter.The wavelet-based coder significantly improves the coding efficiency of the base layer compared with MPEG-4 ASP(Advanced Simple Profile)and H.26L TML9.The PFGS coding is a significant improvement over MPEG-4 FGS coding at the enhancement layer.Experiments show that single layer coding efficiency gain of the proposed scheme is about 2.0-3.0dB and 0.3-1.0dB higher than that of MPEG-4 ASP and H.26L TML9,respectively.The overall coding efficiency gain of the proposed scheme is about 4.0-5.0dB higher than that of MPEG04 FGS.

  2. WAVELET-BASED FINE GRANULARITY SCALABLE VIDEO CODING

    Institute of Scientific and Technical Information of China (English)

    Zhang Jiangshan; Zhu Guangxi

    2003-01-01

    This letter proposes an efficient wavelet-based Fine Granularity Scalable (FGS)coding scheme, where the base layer is encoded with a newly designed wavelet-based coder, and the enhancement layer is encoded with Progressive Fine Granularity Scalable (PFGS) coding.This algorithm involves multi-frame motion compensation, rate-distortion optimizing strategy with Lagrangian cost function and context-based adaptive arithmetic coding. In order to improve efficiency of the enhancement layer coding, an improved motion estimation scheme that uses both information from the base layer and the enhancement layer is also proposed in this letter. The wavelet-based coder significantly improves the coding efficiency of the base layer compared with MPEG-4 ASP (Advanced Simple Profile) and H.26L TML9. The PFGS coding is a significant improvement over MPEG-4 FGS coding at the enhancement layer. Experiments show that single layer coding efficiency gain of the proposed scheme is about 2.0-3.0dB and 0.3-1.0dB higher than that of MPEG-4 ASP and H.26L TML9, respectively. The overall coding efficiency gain of the proposed scheme is about 4.0-5.0dB higher than that of MPEG-4 FGS.

  3. On Converting Secret Sharing Scheme to Visual Secret Sharing Scheme

    Directory of Open Access Journals (Sweden)

    Wang Daoshun

    2010-01-01

    Full Text Available Abstract Traditional Secret Sharing (SS schemes reconstruct secret exactly the same as the original one but involve complex computation. Visual Secret Sharing (VSS schemes decode the secret without computation, but each share is m times as big as the original and the quality of the reconstructed secret image is reduced. Probabilistic visual secret sharing (Prob.VSS schemes for a binary image use only one subpixel to share the secret image; however the probability of white pixels in a white area is higher than that in a black area in the reconstructed secret image. SS schemes, VSS schemes, and Prob. VSS schemes have various construction methods and advantages. This paper first presents an approach to convert (transform a -SS scheme to a -VSS scheme for greyscale images. The generation of the shadow images (shares is based on Boolean XOR operation. The secret image can be reconstructed directly by performing Boolean OR operation, as in most conventional VSS schemes. Its pixel expansion is significantly smaller than that of VSS schemes. The quality of the reconstructed images, measured by average contrast, is the same as VSS schemes. Then a novel matrix-concatenation approach is used to extend the greyscale -SS scheme to a more general case of greyscale -VSS scheme.

  4. Polar Coding for Secure Transmission and Key Agreement

    CERN Document Server

    Koyluoglu, O Ozan

    2010-01-01

    Wyner's work on wiretap channels and the recent works on information theoretic security are based on random codes. Achieving information theoretical security with practical coding schemes is of definite interest. In this note, the attempt is to overcome this elusive task by employing the polar coding technique of Ar{\\i}kan. It is shown that polar codes achieve non-trivial perfect secrecy rates for binary-input degraded wiretap channels while enjoying their low encoding-decoding complexity. In the special case of symmetric main and eavesdropper channels, this coding technique achieves the secrecy capacity. Next, fading erasure wiretap channels are considered and a secret key agreement scheme is proposed, which requires only the statistical knowledge of the eavesdropper channel state information (CSI). The enabling factor is the creation of advantage over Eve, by blindly using the proposed scheme over each fading block, which is then exploited with privacy amplification techniques to generate secret keys.

  5. Scalable still image coding based on wavelet

    Science.gov (United States)

    Yan, Yang; Zhang, Zhengbing

    2005-02-01

    The scalable image coding is an important objective of the future image coding technologies. In this paper, we present a kind of scalable image coding scheme based on wavelet transform. This method uses the famous EZW (Embedded Zero tree Wavelet) algorithm; we give a high-quality encoding to the ROI (region of interest) of the original image and a rough encoding to the rest. This method is applied well in limited memory space condition, and we encode the region of background according to the memory capacity. In this way, we can store the encoded image in limited memory space easily without losing its main information. Simulation results show it is effective.

  6. A Fast Fractal Image Compression Coding Method

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Fast algorithms for reducing encoding complexity of fractal image coding have recently been an important research topic. Search of the best matched domain block is the most computation intensive part of the fractal encoding process. In this paper, a fast fractal approximation coding scheme implemented on a personal computer based on matching in range block's neighbours is presented. Experimental results show that the proposed algorithm is very simple in implementation, fast in encoding time and high in compression ratio while PSNR is almost the same as compared with Barnsley's fractal block coding .

  7. Coding Transparency in Object-Based Video

    DEFF Research Database (Denmark)

    Aghito, Shankar Manuel; Forchhammer, Søren

    2006-01-01

    A novel algorithm for coding gray level alpha planes in object-based video is presented. The scheme is based on segmentation in multiple layers. Different coders are specifically designed for each layer. In order to reduce the bit rate, cross-layer redundancies as well as temporal correlation...

  8. On Delay and Security in Network Coding

    Science.gov (United States)

    Dikaliotis, Theodoros K.

    2013-01-01

    In this thesis, delay and security issues in network coding are considered. First, we study the delay incurred in the transmission of a fixed number of packets through acyclic networks comprised of erasure links. The two transmission schemes studied are routing with hop-by-hop retransmissions, where every node in the network simply stores and…

  9. Quantum Teleportation and Superdense Coding via W-Class States

    Institute of Scientific and Technical Information of China (English)

    YAN Jun; WU Huai-Zhi; YANG Zhen-Biao; ZHENG Shi-Biao

    2008-01-01

    According to the protocol of Agrawal et al., we propose a cavity QED scheme for realization of teleportation and dense coding. Instead of using EPR states and GHZ states, our scheme is more insensitive to the loss of one particle by using a W-class state as a quantum channel. Besides, our scheme is immune to thermal field, and does not require the cavity to remain in the vacuum state throughout the procedure.

  10. INTERLEAVING SCHEME FOR MULTICARRIER CDMA SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Shi Feng; Cheng Shixin

    2004-01-01

    In MultiCarrier Code-Division Multiple-Access (MC-CDMA) system, the received signals scattered in the frequency domain are combined to get frequency diversity gain. However, the frequency diversity gain is limited because of correlation between subcarriers. A novel interleaving scheme for MC-CDMA system is proposed in this paper. A circular shifting register is introduced into each subcarrier branch to decrease the correlation between subcarriers. By using interleaving, frequency diversity gain of system is increased. System structure and model with interleaver are discussed. In the case of multiple users, Parallel Interference Cancellation (PIC) technique is also introduced. Computer simulations demonstrate the performance of proposed scheme, and the performance comparison of MC-CDMA with interleaver and conventional MC-CDMA system is shown as well.

  11. Strong Trinucleotide Circular Codes

    Directory of Open Access Journals (Sweden)

    Christian J. Michel

    2011-01-01

    Full Text Available Recently, we identified a hierarchy relation between trinucleotide comma-free codes and trinucleotide circular codes (see our previous works. Here, we extend our hierarchy with two new classes of codes, called DLD and LDL codes, which are stronger than the comma-free codes. We also prove that no circular code with 20 trinucleotides is a DLD code and that a circular code with 20 trinucleotides is comma-free if and only if it is a LDL code. Finally, we point out the possible role of the symmetric group ∑4 in the mathematical study of trinucleotide circular codes.

  12. A comparison of SPH schemes for the compressible Euler equations

    Science.gov (United States)

    Puri, Kunal; Ramachandran, Prabhu

    2014-01-01

    We review the current state-of-the-art Smoothed Particle Hydrodynamics (SPH) schemes for the compressible Euler equations. We identify three prototypical schemes and apply them to a suite of test problems in one and two dimensions. The schemes are in order, standard SPH with an adaptive density kernel estimation (ADKE) technique introduced Sigalotti et al. (2008) [44], the variational SPH formulation of Price (2012) [33] (referred herein as the MPM scheme) and the Godunov type SPH (GSPH) scheme of Inutsuka (2002) [12]. The tests investigate the accuracy of the inviscid discretizations, shock capturing ability and the particle settling behavior. The schemes are found to produce nearly identical results for the 1D shock tube problems with the MPM and GSPH schemes being the most robust. The ADKE scheme requires parameter values which must be tuned to the problem at hand. We propose an addition of an artificial heating term to the GSPH scheme to eliminate unphysical spikes in the thermal energy at the contact discontinuity. The resulting modification is simple and can be readily incorporated in existing codes. In two dimensions, the differences between the schemes is more evident with the quality of results determined by the particle distribution. In particular, the ADKE scheme shows signs of particle clumping and irregular motion for the 2D strong shock and Sedov point explosion tests. The noise in particle data is linked with the particle distribution which remains regular for the Hamiltonian formulations (MPM and GSPH) and becomes irregular for the ADKE scheme. In the interest of reproducibility, we make available our implementation of the algorithms and test problems discussed in this work.

  13. Distributed Joint Source-Channel Coding for arbitrary memoryless correlated sources and Source coding for Markov correlated sources using LDPC codes

    CERN Document Server

    Aggarwal, Vaneet

    2008-01-01

    In this paper, we give a distributed joint source channel coding scheme for arbitrary correlated sources for arbitrary point in the Slepian-Wolf rate region, and arbitrary link capacities using LDPC codes. We consider the Slepian-Wolf setting of two sources and one destination, with one of the sources derived from the other source by some correlation model known at the decoder. Distributed encoding and separate decoding is used for the two sources. We also give a distributed source coding scheme when the source correlation has memory to achieve any point in the Slepian-Wolf rate achievable region. In this setting, we perform separate encoding but joint decoding.

  14. Research of Wavelet Based Multicarrier Modulation System with Near Shannon Limited Codes

    Institute of Scientific and Technical Information of China (English)

    ZHANGHaixia; YUANDongfeng; ZHAOFeng

    2005-01-01

    In this paper, by using turbo codes and Low density parity codes (LDPC) as channel correcting code scheme, Wavelet based multicarrier modulation (WMCM) systems are proposed and investigated on different transmission scenarios. The Bit error rate (BER) performance of these two near Shannon limited codes is simulated and compared with various code parameters. Simulated results show that Turbo coded WMCM (TCWMCM) performs better than LDPC coded WMCM (LDPC-CWMCM) on both AWGN and Rayleigh fading channels when these two kinds of codes are of the same code parameters.

  15. Joint source channel coding using arithmetic codes

    CERN Document Server

    Bi, Dongsheng

    2009-01-01

    Based on the encoding process, arithmetic codes can be viewed as tree codes and current proposals for decoding arithmetic codes with forbidden symbols belong to sequential decoding algorithms and their variants. In this monograph, we propose a new way of looking at arithmetic codes with forbidden symbols. If a limit is imposed on the maximum value of a key parameter in the encoder, this modified arithmetic encoder can also be modeled as a finite state machine and the code generated can be treated as a variable-length trellis code. The number of states used can be reduced and techniques used fo

  16. On the role of code comparisons in verification and validation.

    Energy Technology Data Exchange (ETDEWEB)

    Oberkampf, William Louis; Trucano, Timothy Guy; Pilch, Martin M.

    2003-08-01

    This report presents a perspective on the role of code comparison activities in verification and validation. We formally define the act of code comparison as the Code Comparison Principle (CCP) and investigate its application in both verification and validation. One of our primary conclusions is that the use of code comparisons for validation is improper and dangerous. We also conclude that while code comparisons may be argued to provide a beneficial component in code verification activities, there are higher quality code verification tasks that should take precedence. Finally, we provide a process for application of the CCP that we believe is minimal for achieving benefit in verification processes.

  17. Public Law 94-553-Oct. 19, 1976. An Act For the General Revision of the Copyright Law, Title 17 of the United States Code, and for Other Purposes. Title 17-Copyrights. Ninety-Fourth Congress.

    Science.gov (United States)

    Congress of the U.S., Washington, DC.

    The copyright law of the United States is amended in its entirety by this act that takes effect in 1978. Literary works; musical works; dramatic works; pantomimes and choreographic works; pictorial, graphic, and sculptural works; motion pictures and other audiovisual works; and sound recordings are included in the subject matter of copyright.…

  18. Optimal Codes for the Burst Erasure Channel

    Science.gov (United States)

    Hamkins, Jon

    2010-01-01

    Deep space communications over noisy channels lead to certain packets that are not decodable. These packets leave gaps, or bursts of erasures, in the data stream. Burst erasure correcting codes overcome this problem. These are forward erasure correcting codes that allow one to recover the missing gaps of data. Much of the recent work on this topic concentrated on Low-Density Parity-Check (LDPC) codes. These are more complicated to encode and decode than Single Parity Check (SPC) codes or Reed-Solomon (RS) codes, and so far have not been able to achieve the theoretical limit for burst erasure protection. A block interleaved maximum distance separable (MDS) code (e.g., an SPC or RS code) offers near-optimal burst erasure protection, in the sense that no other scheme of equal total transmission length and code rate could improve the guaranteed correctible burst erasure length by more than one symbol. The optimality does not depend on the length of the code, i.e., a short MDS code block interleaved to a given length would perform as well as a longer MDS code interleaved to the same overall length. As a result, this approach offers lower decoding complexity with better burst erasure protection compared to other recent designs for the burst erasure channel (e.g., LDPC codes). A limitation of the design is its lack of robustness to channels that have impairments other than burst erasures (e.g., additive white Gaussian noise), making its application best suited for correcting data erasures in layers above the physical layer. The efficiency of a burst erasure code is the length of its burst erasure correction capability divided by the theoretical upper limit on this length. The inefficiency is one minus the efficiency. The illustration compares the inefficiency of interleaved RS codes to Quasi-Cyclic (QC) LDPC codes, Euclidean Geometry (EG) LDPC codes, extended Irregular Repeat Accumulate (eIRA) codes, array codes, and random LDPC codes previously proposed for burst erasure

  19. An Orbit And Dispersion Correction Scheme for the PEP II

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Y.; Donald, M.; Shoaee, H.; White, G.; Yasukawa, L.A.; /SLAC

    2011-09-01

    To achieve optimum luminosity in a storage ring it is vital to control the residual vertical dispersion. In the original PEP storage ring, a scheme to control the residual dispersion function was implemented using the ring orbit as the controlling element. The 'best' orbit not necessarily giving the lowest vertical dispersion. A similar scheme has been implemented in both the on-line control code and in the simulation code LEGO. The method involves finding the response matrices (sensitivity of orbit/dispersion at each Beam-Position-Monitor (BPM) to each orbit corrector) and solving in a least squares sense for minimum orbit, dispersion function or both. The optimum solution is usually a subset of the full least squares solution. A scheme of simultaneously correcting the orbits and dispersion has been implemented in the simulation code and on-line control system for PEP-II. The scheme is based on the eigenvector decomposition method. An important ingredient of the scheme is to choose the optimum eigenvectors that minimize the orbit, dispersion and corrector strength. Simulations indicate this to be a very effective way to control the vertical residual dispersion.

  20. Modeling and Simulation of Downlink Subcarrier Allocation Schemes in LTE

    DEFF Research Database (Denmark)

    Popovska Avramova, Andrijana; Yan, Ying; Dittmann, Lars

    2012-01-01

    The efficient utilization of the air interface in the LTE standard is achieved through a combination of subcarrier allocation schemes, adaptive modulation and coding, and transmission power allotment. The scheduler in the base station has a major role in achieving the required QoS and the overall...

  1. A New Deferred Sentencing Scheme

    Directory of Open Access Journals (Sweden)

    N. K. Chakravarti

    1968-10-01

    Full Text Available A new deferred sentencing scheme resembling double sampling scheme has been suggested from viewpoint of operational and administrative. It is recommended particularly when the inspection is destructive. The O.C. curves of the scheme for two sample sizes of 5 and 10 have been given.

  2. Bonus schemes and trading activity

    NARCIS (Netherlands)

    Pikulina, E.S.; Renneboog, L.D.R.; ter Horst, J.R.; Tobler, P.N.

    2014-01-01

    Little is known about how different bonus schemes affect traders' propensity to trade and which bonus schemes improve traders' performance. We study the effects of linear versus threshold bonus schemes on traders' behavior. Traders buy and sell shares in an experimental stock market on the basis of

  3. Bonus Schemes and Trading Activity

    NARCIS (Netherlands)

    Pikulina, E.S.; Renneboog, L.D.R.; Ter Horst, J.R.; Tobler, P.N.

    2013-01-01

    Abstract: Little is known about how different bonus schemes affect traders’ propensity to trade and which bonus schemes improve traders’ performance. We study the effects of linear versus threshold (convex) bonus schemes on traders’ behavior. Traders purchase and sell shares in an experimental stock

  4. Bonus schemes and trading activity

    NARCIS (Netherlands)

    Pikulina, E.S.; Renneboog, L.D.R.; ter Horst, J.R.; Tobler, P.N.

    2014-01-01

    Little is known about how different bonus schemes affect traders' propensity to trade and which bonus schemes improve traders' performance. We study the effects of linear versus threshold bonus schemes on traders' behavior. Traders buy and sell shares in an experimental stock market on the basis of

  5. Two Improved Digital Signature Schemes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, two improved digital signature schemes are presented based on the design of directed signaturescheme [3]. The peculiarity of the system is that only if the scheme is specific recipient, the signature is authenticated.Since the scheme adds the screen of some information parameters, the difficulty of deciphered keys and the security ofdigital signature system are increased.

  6. Independent Source Coding for Control over Noiseless Channels

    DEFF Research Database (Denmark)

    da Silva, Eduardo; Derpich, Milan; Østergaard, Jan

    2010-01-01

    By focusing on a class of source coding schemes built around entropy coded dithered quantizers, we develop a framework to deal with average data-rate constraints in a tractable manner that combines ideas from both information and control theories. We focus on a situation where a noisy linear system...

  7. Dependency graph for code analysis on emerging architectures

    Energy Technology Data Exchange (ETDEWEB)

    Shashkov, Mikhail Jurievich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lipnikov, Konstantin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-08

    Direct acyclic dependency (DAG) graph is becoming the standard for modern multi-physics codes.The ideal DAG is the true block-scheme of a multi-physics code. Therefore, it is the convenient object for insitu analysis of the cost of computations and algorithmic bottlenecks related to statistical frequent data motion and dymanical machine state.

  8. Integrated code development for studying laser driven plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Takabe, Hideaki; Nagatomo, Hideo; Sunahara, Atsusi; Ohnishi, Naofumi; Naruo, Syuji; Mima, Kunioki [Osaka Univ., Suita (Japan). Inst. of Laser Engineering

    1998-03-01

    Present status and plan for developing an integrated implosion code are briefly explained by focusing on motivation, numerical scheme and issues to be developed more. Highly nonlinear stage of Rayleigh-Taylor instability of ablation front by laser irradiation has been simulated so as to be compared with model experiments. Improvement in transport and rezoning/remapping algorithms in ILESTA code is described. (author)

  9. Codes, Ciphers, and Cryptography--An Honors Colloquium

    Science.gov (United States)

    Karls, Michael A.

    2010-01-01

    At the suggestion of a colleague, I read "The Code Book", [32], by Simon Singh to get a basic introduction to the RSA encryption scheme. Inspired by Singh's book, I designed a Ball State University Honors Colloquium in Mathematics for both majors and non-majors, with material coming from "The Code Book" and many other sources. This course became…

  10. Single integrated device for optical CDMA code processing in dual-code environment.

    Science.gov (United States)

    Huang, Yue-Kai; Glesk, Ivan; Greiner, Christoph M; Iazkov, Dmitri; Mossberg, Thomas W; Wang, Ting; Prucnal, Paul R

    2007-06-11

    We report on the design, fabrication and performance of a matching integrated optical CDMA encoder-decoder pair based on holographic Bragg reflector technology. Simultaneous encoding/decoding operation of two multiple wavelength-hopping time-spreading codes was successfully demonstrated and shown to support two error-free OCDMA links at OC-24. A double-pass scheme was employed in the devices to enable the use of longer code length.

  11. Initial code exchange for asynchronous TR-UWB ad hoc networks

    NARCIS (Netherlands)

    Djapic, R.; Shi, N.; Leus, G.

    2007-01-01

    In this paper we present an initial code exchange scheme for a transmit-reference ultra wide-band (TR-UWB) system. We exploit the facts that a TR-UWB transceiver scheme allows for simultaneous transmission and reception as well as detection and separation of distinct users with the same code even if

  12. Model Children's Code.

    Science.gov (United States)

    New Mexico Univ., Albuquerque. American Indian Law Center.

    The Model Children's Code was developed to provide a legally correct model code that American Indian tribes can use to enact children's codes that fulfill their legal, cultural and economic needs. Code sections cover the court system, jurisdiction, juvenile offender procedures, minor-in-need-of-care, and termination. Almost every Code section is…

  13. CONSIDERATIONS CONCERNING GUARANTEE SCHEMES

    Directory of Open Access Journals (Sweden)

    EMILIA CLIPICI

    2013-05-01

    Full Text Available When a large withdrawal from banks occurs, customers withdraw their deposits, so banks are likely to go bankrupt because of liquidity problems. There are several mechanisms that allow the banking system to avoid the phenomenon of massive withdrawals from banks. The most effective one is the deposit insurance. The deposit insurance is seen primarily as a means of protecting depositors of credit institutions, and secondly as a means of ensuring the stability of the banking system. This article described deposit guarantee scheme in Romania and other country.

  14. Password Authentication Scheme with Secured Login Interface

    Directory of Open Access Journals (Sweden)

    AKINWALE A. Taofiki

    2009-12-01

    Full Text Available This paper presents a novel solution to the age long problem of password security at input level. In our solution, each of the various characters from which a password could be composed is encoded with a random single digit integer and presented to the user via an input interface form. A legitimate user entering his password only needs to carefully study the sequence of code that describe his password, and then enter these code in place of his actual password characters. This approach does not require the input code to be hidden from anyone or converted to placeholder characters for security reasons. Our solution engine regenerates new code for each character each time the carriage return key is struck, producing a hardened password that is convincingly more secure than conventional password entry system against both online and offline attackers. Using empirical data and a prototype implementation of our scheme, we give evidence that our approach is viable in practice, in terms of ease of use, improved security, and performance.

  15. Myths and realities of rateless coding

    KAUST Repository

    Bonello, Nicholas

    2011-08-01

    Fixed-rate and rateless channel codes are generally treated separately in the related research literature and so, a novice in the field inevitably gets the impression that these channel codes are unrelated. By contrast, in this treatise, we endeavor to further develop a link between the traditional fixed-rate codes and the recently developed rateless codes by delving into their underlying attributes. This joint treatment is beneficial for two principal reasons. First, it facilitates the task of researchers and practitioners, who might be familiar with fixed-rate codes and would like to jump-start their understanding of the recently developed concepts in the rateless reality. Second, it provides grounds for extending the use of the well-understood codedesign tools-originally contrived for fixed-rate codes-to the realm of rateless codes. Indeed, these versatile tools proved to be vital in the design of diverse fixed-rate-coded communications systems, and thus our hope is that they will further elucidate the associated performance ramifications of the rateless coded schemes. © 2011 IEEE.

  16. Overhead analysis of universal concatenated quantum codes

    Science.gov (United States)

    Chamberland, Christopher; Jochym-O'Connor, Tomas; Laflamme, Raymond

    2017-02-01

    We analyze the resource overhead of recently proposed methods for universal fault-tolerant quantum computation using concatenated codes. Namely, we examine the concatenation of the 7-qubit Steane code with the 15-qubit Reed-Muller code, which allows for the construction of the 49- and 105-qubit codes that do not require the need for magic state distillation for universality. We compute a lower bound for the adversarial noise threshold of the 105-qubit code and find it to be 8.33 ×10-6. We obtain a depolarizing noise threshold for the 49-qubit code of 9.69 ×10-4 which is competitive with the 105-qubit threshold result of 1.28 ×10-3 . We then provide lower bounds on the resource requirements of the 49- and 105-qubit codes and compare them with the surface code implementation of a logical T gate using magic state distillation. For the sampled input error rates and noise model, we find that the surface code achieves a smaller overhead compared to our concatenated schemes.

  17. An arbitrated quantum signature scheme based on entanglement swapping with signer anonymity

    Science.gov (United States)

    Li, Wei; Fan, Ming-Yu; Wang, Guang-Wei

    2012-12-01

    In this paper an arbitrated quantum signature scheme based on entanglement swapping is proposed. In this scheme a message to be signed is coded with unitary operators. Combining quantum measurement with quantum encryption, the signer can generate the signature for a given message. Combining the entangled states generated by the TTP's Bell measurement with the signature information, the verifier can verify the authentication of a signature through a single quantum state measurement. Compared with previous schemes, our scheme is more efficient and less complex, furthermore, our scheme can ensure the anonymity of the signer.

  18. Multilevel LDPC Codes Design for Multimedia Communication CDMA System

    Directory of Open Access Journals (Sweden)

    Hou Jia

    2004-01-01

    Full Text Available We design multilevel coding (MLC with a semi-bit interleaved coded modulation (BICM scheme based on low density parity check (LDPC codes. Different from the traditional designs, we joined the MLC and BICM together by using the Gray mapping, which is suitable to transmit the data over several equivalent channels with different code rates. To perform well at signal-to-noise ratio (SNR to be very close to the capacity of the additive white Gaussian noise (AWGN channel, random regular LDPC code and a simple semialgebra LDPC (SA-LDPC code are discussed in MLC with parallel independent decoding (PID. The numerical results demonstrate that the proposed scheme could achieve both power and bandwidth efficiency.

  19. The neutral emergence of error minimized genetic codes superior to the standard genetic code.

    Science.gov (United States)

    Massey, Steven E

    2016-11-07

    The standard genetic code (SGC) assigns amino acids to codons in such a way that the impact of point mutations is reduced, this is termed 'error minimization' (EM). The occurrence of EM has been attributed to the direct action of selection, however it is difficult to explain how the searching of alternative codes for an error minimized code can occur via codon reassignments, given that these are likely to be disruptive to the proteome. An alternative scenario is that EM has arisen via the process of genetic code expansion, facilitated by the duplication of genes encoding charging enzymes and adaptor molecules. This is likely to have led to similar amino acids being assigned to similar codons. Strikingly, we show that if during code expansion the most similar amino acid to the parent amino acid, out of the set of unassigned amino acids, is assigned to codons related to those of the parent amino acid, then genetic codes with EM superior to the SGC easily arise. This scheme mimics code expansion via the gene duplication of charging enzymes and adaptors. The result is obtained for a variety of different schemes of genetic code expansion and provides a mechanistically realistic manner in which EM has arisen in the SGC. These observations might be taken as evidence for self-organization in the earliest stages of life. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Modulation schemes and error-probability of MIL-STD-1773 fiber optic data bus

    Science.gov (United States)

    Yude, Ni; Jian, Wang; Zhang, Jian-Guo

    2005-11-01

    Based on the analysis of the MIL-STD-1773 data bus modulation scheme, two optical modulation schemes are proposed for designing this kind of data bus, namely, partial tri-level Manchester II bi-phase coding (PTMBC) and extended Manchester II bi-phase coding with beginning-stopping flags (EMBC-BSF), which can efficiently solve the problem related to three outputs at a MIL-STD-1773 optical receiver with low complexity. Then we focus on the analysis of error probability and optical receiver sensitivity for MIL-STD-1773 data buses with three modulation schemes of Manchester II bi-phase coding, PTMBC , and EMBC-BSF. The results show that both the PTMBC and EMBC-BSF modulation schemes have almost the identical and worse receiver sensitivity than that of the Manchester bi-level coding by ~3dB.

  1. Turbo Codes Based on Time-Variant Memory-1 Convolutional Codes over Fq

    CERN Document Server

    Liva, Gianluigi; Scalise, Sandro; Chiani, Marco

    2011-01-01

    Two classes of turbo codes over high-order finite fields are introduced. The codes are derived from a particular protograph sub-ensemble of the (dv=2,dc=3) low-density parity-check code ensemble. A first construction is derived as a parallel concatenation of two non-binary, time-variant accumulators. The second construction is based on the serial concatenation of a non-binary, time-variant differentiator and of a non-binary, time-variant accumulator, and provides a highly-structured flexible encoding scheme for (dv=2,dc=4) ensemble codes. A cycle graph representation is provided. The proposed codes can be decoded efficiently either as low-density parity-check codes (via belief propagation decoding over the codes bipartite graph) or as turbo codes (via the forward-backward algorithm applied to the component codes trellis). The forward-backward algorithm for symbol maximum a posteriori decoding of the component codes is illustrated and simplified by means of the fast Fourier transform. The proposed codes provid...

  2. Secure mediated certificateless signature scheme

    Institute of Scientific and Technical Information of China (English)

    YANG Chen; MA Wen-ping; WANG Xin-mei

    2007-01-01

    Ju et al proposed a certificateless signature scheme with instantaneous revocation by introducing security mediator (SEM) mechanism. This article presents a detailed cryptoanalysis of this scheme and shows that, in their proposed scheme, once a valid signature has been produced, the signer can recover his private key information and the instantaneous revocation property will be damaged. Furthermore, an improved mediated signature scheme, which can eliminate these disadvantages, is proposed, and security proof of the improved scheme under elliptic curve factorization problem (ECFP) assumption and bilinear computational diffie-hellman problem (BCDH) assumption is also proposed.

  3. Recent developments in the Los Alamos radiation transport code system

    Energy Technology Data Exchange (ETDEWEB)

    Forster, R.A.; Parsons, K. [Los Alamos National Lab., NM (United States)

    1997-06-01

    A brief progress report on updates to the Los Alamos Radiation Transport Code System (LARTCS) for solving criticality and fixed-source problems is provided. LARTCS integrates the Diffusion Accelerated Neutral Transport (DANT) discrete ordinates codes with the Monte Carlo N-Particle (MCNP) code. The LARCTS code is being developed with a graphical user interface for problem setup and analysis. Progress in the DANT system for criticality applications include a two-dimensional module which can be linked to a mesh-generation code and a faster iteration scheme. Updates to MCNP Version 4A allow statistical checks of calculated Monte Carlo results.

  4. An efficient adaptive arithmetic coding image compression technology

    Institute of Scientific and Technical Information of China (English)

    Wang Xing-Yuan; Yun Jiao-Jiao; Zhang Yong-Lei

    2011-01-01

    This paper proposes an efficient lossless image compression scheme for still images based on an adaptive arithmetic coding compression algorithm.The algorithm increases the image coding compression rate and ensures the quality of the decoded image combined with the adaptive probability model and predictive coding.The use of adaptive models for each encoded image block dynamically estimates the probability of the relevant image block.The decoded image block can accurately recover the encoded image according to the code book information.We adopt an adaptive arithmetic coding algorithm for image compression that greatly improves the image compression rate.The results show that it is an effective compression technology.

  5. Source Coding Using Families of Universal Hash Functions

    OpenAIRE

    Koga, Hiroki

    2007-01-01

    This correspondence is concerned with new connections between source coding and two kinds of families of hash functions known as the families of universal hash functions and N-strongly universal hash functions, where N ges 2 is an integer. First, it is pointed out that such families contain classes of well-known source codes such as bin codes and linear codes. Next, performance of a source coding scheme using either of the two kinds of families is evaluated. An upper bound on the expectation ...

  6. Universal coding for correlated sources with complementary delivery

    CERN Document Server

    Kimura, Akisato; Kuzuoka, Shigeaki

    2007-01-01

    This paper deals with a universal coding problem for a certain kind of multiterminal source coding system that we call the complementary delivery coding system. In this system, messages from two correlated sources are jointly encoded, and each decoder has access to one of the two messages to enable it to reproduce the other message. Both fixed-to-fixed length and fixed-to-variable length lossless coding schemes are considered. Explicit constructions of universal codes and bounds of the error probabilities are clarified via type-theoretical and graph-theoretical analyses. [[Keywords

  7. Using Concatenated Quantum Codes for Universal Fault-Tolerant Quantum Gates

    Science.gov (United States)

    Jochym-O'Connor, Tomas; Laflamme, Raymond

    2014-01-01

    We propose a method for universal fault-tolerant quantum computation using concatenated quantum error correcting codes. The concatenation scheme exploits the transversal properties of two different codes, combining them to provide a means to protect against low-weight arbitrary errors. We give the required properties of the error correcting codes to ensure universal fault tolerance and discuss a particular example using the 7-qubit Steane and 15-qubit Reed-Muller codes. Namely, other than computational basis state preparation as required by the DiVincenzo criteria, our scheme requires no special ancillary state preparation to achieve universality, as opposed to schemes such as magic state distillation. We believe that optimizing the codes used in such a scheme could provide a useful alternative to state distillation schemes that exhibit high overhead costs.

  8. Improved Iterative Decoding of Network-Channel Codes for Multiple-Access Relay Channel.

    Science.gov (United States)

    Majumder, Saikat; Verma, Shrish

    2015-01-01

    Cooperative communication using relay nodes is one of the most effective means of exploiting space diversity for low cost nodes in wireless network. In cooperative communication, users, besides communicating their own information, also relay the information of other users. In this paper we investigate a scheme where cooperation is achieved using a common relay node which performs network coding to provide space diversity for two information nodes transmitting to a base station. We propose a scheme which uses Reed-Solomon error correcting code for encoding the information bit at the user nodes and convolutional code as network code, instead of XOR based network coding. Based on this encoder, we propose iterative soft decoding of joint network-channel code by treating it as a concatenated Reed-Solomon convolutional code. Simulation results show significant improvement in performance compared to existing scheme based on compound codes.

  9. A simple data compression scheme for binary images of bacteria compared with commonly used image data compression schemes.

    Science.gov (United States)

    Wilkinson, M H

    1994-04-01

    A run length code compression scheme of extreme simplicity, used for image storage in an automated bacterial morphometry system, is compared with more common compression schemes, such as are used in the tag image file format. These schemes are Lempel-Ziv and Welch (LZW), Macintosh Packbits, and CCITT Group 3 Facsimile 1-dimensional modified Huffman run length code. In a set of 25 images consisting of full microscopic fields of view of bacterial slides, the method gave a 10.3-fold compression: 1.074 times better than LZW. In a second set of images of single areas of interest within each field of view, compression ratios of over 600 were obtained, 12.8 times that of LZW. The drawback of the system is its bad worst case performance. The method could be used in any application requiring storage of binary images of relatively small objects with fairly large spaces in between.

  10. Best Effort and Practice Activation Codes

    CERN Document Server

    Gans, Gerhard de Koning

    2011-01-01

    Activation Codes are used in many different digital services and known by many different names including voucher, e-coupon and discount code. In this paper we focus on a specific class of ACs that are short, human-readable, fixed-length and represent value. Even though this class of codes is extensively used there are no general guidelines for the design of Activation Code schemes. We discuss different methods that are used in practice and propose BEPAC, a new Activation Code scheme that provides both authenticity and confidentiality. The small message space of activation codes introduces some problems that are illustrated by an adaptive chosen-plaintext attack (CPA-2) on a general 3-round Feistel network of size 2^(2n). This attack recovers the complete permutation from at most 2^(n+2) plaintext-ciphertext pairs. For this reason, BEPAC is designed in such a way that authenticity and confidentiality are independent of each other, i.e. loss of confidentiality does not imply loss of authenticity.

  11. Efficient Quantum Private Communication Based on Dynamic Control Code Sequence

    Science.gov (United States)

    Cao, Zheng-Wen; Feng, Xiao-Yi; Peng, Jin-Ye; Zeng, Gui-Hua; Qi, Jin

    2016-12-01

    Based on chaos and quantum properties, we propose a quantum private communication scheme with dynamic control code sequence. The initial sequence is obtained via chaotic systems, and the control code sequence is derived by grouping, XOR and extracting. A shift cycle algorithm is designed to enable the dynamic change of control code sequence. Analysis shows that transmission efficiency could reach 100 % with high dynamics and security.

  12. Context based Coding of Quantized Alpha Planes for Video Objects

    DEFF Research Database (Denmark)

    Aghito, Shankar Manuel; Forchhammer, Søren

    2002-01-01

    In object based video, each frame is a composition of objects that are coded separately. The composition is performed through the alpha plane that represents the transparency of the object. We present an alternative to MPEG-4 for coding of alpha planes that considers their specific properties....... Comparisons in terms of rate and distortion are provided, showing that the proposed coding scheme for still alpha planes is better than the algorithms for I-frames used in MPEG-4....

  13. Hybrid Coding of Image Sequences by Using Wavelet Transform

    Directory of Open Access Journals (Sweden)

    M. Surin

    2000-04-01

    Full Text Available In this paper, a new method of hybrid coding of image sequences byusing wavelet transform is proposed. The basic MPEG scheme with DCT hasbeen modificated in sense of replacement DCT by wavelet transform. Inthe proposed method, the motion estimation and compensation are usedfor motion vectors calculation and different frame between currentframe and compensated frame is coded by using wavelet transform. Someexperimental results of image sequences coding by using a new methodare presented.

  14. Efficient Quantum Private Communication Based on Dynamic Control Code Sequence

    Science.gov (United States)

    Cao, Zheng-Wen; Feng, Xiao-Yi; Peng, Jin-Ye; Zeng, Gui-Hua; Qi, Jin

    2017-04-01

    Based on chaos and quantum properties, we propose a quantum private communication scheme with dynamic control code sequence. The initial sequence is obtained via chaotic systems, and the control code sequence is derived by grouping, XOR and extracting. A shift cycle algorithm is designed to enable the dynamic change of control code sequence. Analysis shows that transmission efficiency could reach 100 % with high dynamics and security.

  15. Rateless feedback codes

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Koike-Akino, Toshiaki; Orlik, Philip

    2012-01-01

    This paper proposes a concept called rateless feedback coding. We redesign the existing LT and Raptor codes, by introducing new degree distributions for the case when a few feedback opportunities are available. We show that incorporating feedback to LT codes can significantly decrease both...... the coding overhead and the encoding/decoding complexity. Moreover, we show that, at the price of a slight increase in the coding overhead, linear complexity is achieved with Raptor feedback coding....

  16. Multiple description scalable video coding based on 3D lifted wavelet transform

    Institute of Scientific and Technical Information of China (English)

    JIANG Gang-yi; YU Mei; YU Zhou; YE Xi-en; ZHANG Wen-qin; KIM Yong-deak

    2006-01-01

    In this work, a new method to deal with the unconnected pixels in motion compensated temporal filtering (MCTF) is presented, which is designed to improve the performance of 3D lifted wavelet coding. Furthermore, multiple description scalable coding (MDSC) is investigated, and novel MDSC schemes based on 3D wavelet coding are proposed, using the lifting implementation of temporal filtering. The proposed MDSC schemes can avoid the mismatch problem in multiple description video coding, and have high scalability and robustness of video transmission. Experimental results showed that the proposed schemes are feasible and adequately effective.

  17. QR code based noise-free optical encryption and decryption of a gray scale image

    Science.gov (United States)

    Jiao, Shuming; Zou, Wenbin; Li, Xia

    2017-03-01

    In optical encryption systems, speckle noise is one major challenge in obtaining high quality decrypted images. This problem can be addressed by employing a QR code based noise-free scheme. Previous works have been conducted for optically encrypting a few characters or a short expression employing QR codes. This paper proposes a practical scheme for optically encrypting and decrypting a gray-scale image based on QR codes for the first time. The proposed scheme is compatible with common QR code generators and readers. Numerical simulation results reveal the proposed method can encrypt and decrypt an input image correctly.

  18. On Detecting Pollution Attacks in Inter-Session Network Coding

    CERN Document Server

    Le, Anh

    2011-01-01

    Dealing with pollution attacks in inter-session network coding is challenging due to the fact that sources, in addition to intermediate nodes, can be malicious. In this work, we precisely define corrupted packets in inter-session pollution based on the commitment of the source packets. We then propose three detection schemes: one hash-based and two MAC-based schemes: InterMacCPK and SpaceMacPM. InterMacCPK is the first multi-source homomorphic MAC scheme that supports multiple keys. Both MAC schemes can replace traditional MACs, e.g., HMAC, in networks that employ inter-session coding. All three schemes provide in-network detection, are collusion-resistant, and have very low online bandwidth and computation overhead.

  19. Counteracting Byzantine Adversaries with Network Coding: An Overhead Analysis

    CERN Document Server

    Kim, MinJi; Barros, Joao

    2008-01-01

    Network coding increases throughput and is robust against failures and erasures. However, since it allows mixing of information within the network, a single corrupted packet generated by a Byzantine attacker can easily contaminate the information to multiple destinations. In this paper, we study the transmission overhead associated with detecting Byzantine adversaries at a trusted node using network coding. We consider three different schemes: end-to-end error correction, packet-based Byzantine detection scheme, and generation-based Byzantine detection scheme. In end-to-end error correction, it is known that we can correct up to the min-cut between the source and destinations. However, if we use Byzantine detection schemes, we can detect polluted data, drop them, and therefore, only transmit valid data. For the dropped data, the destinations perform erasure correction, which is computationally lighter than error correction. We show that, with enough attackers present in the network, Byzantine detection scheme...

  20. Coding for dummies

    CERN Document Server

    Abraham, Nikhil

    2015-01-01

    Hands-on exercises help you learn to code like a pro No coding experience is required for Coding For Dummies,your one-stop guide to building a foundation of knowledge inwriting computer code for web, application, and softwaredevelopment. It doesn't matter if you've dabbled in coding or neverwritten a line of code, this book guides you through the basics.Using foundational web development languages like HTML, CSS, andJavaScript, it explains in plain English how coding works and whyit's needed. Online exercises developed by Codecademy, a leading online codetraining site, help hone coding skill

  1. Advanced video coding systems

    CERN Document Server

    Gao, Wen

    2015-01-01

    This comprehensive and accessible text/reference presents an overview of the state of the art in video coding technology. Specifically, the book introduces the tools of the AVS2 standard, describing how AVS2 can help to achieve a significant improvement in coding efficiency for future video networks and applications by incorporating smarter coding tools such as scene video coding. Topics and features: introduces the basic concepts in video coding, and presents a short history of video coding technology and standards; reviews the coding framework, main coding tools, and syntax structure of AV

  2. Picturewise inter-view prediction selection for multiview video coding

    Science.gov (United States)

    Huo, Junyan; Chang, Yilin; Li, Ming; Yang, Haitao

    2010-11-01

    Inter-view prediction is introduced in multiview video coding (MVC) to exploit the inter-view correlation. Statistical analyses show that the coding gain benefited from inter-view prediction is unequal among pictures. On the basis of this observation, a picturewise interview prediction selection scheme is proposed. This scheme employs a novel inter-view prediction selection criterion to determine whether it is necessary to apply inter-view prediction to the current coding picture. This criterion is derived from the available coding information of the temporal reference pictures. Experimental results show that the proposed scheme can improve the performance of MVC with a comprehensive consideration of compression efficiency, computational complexity, and random access ability.

  3. Explicit TE/TM scheme for particle beam simulations

    Energy Technology Data Exchange (ETDEWEB)

    Dohlus, M.; Zagorodnov, I.

    2008-10-15

    In this paper we propose an explicit two-level conservative scheme based on a TE/TM like splitting of the field components in time. Its dispersion properties are adjusted to accelerator problems. It is simpler and faster than the implicit version. It does not have dispersion in the longitudinal direction and the dispersion properties in the transversal plane are improved. The explicit character of the new scheme allows a uniformly stable conformal method without iterations and the scheme can be parallelized easily. It assures energy and charge conservation. A version of this explicit scheme for rotationally symmetric structures is free from the progressive time step reducing for higher order azimuthal modes as it takes place for Yee's explicit method used in the most popular electrodynamics codes. (orig.)

  4. A moving mesh unstaggered constrained transport scheme for magnetohydrodynamics

    CERN Document Server

    Mocz, Philip; Springel, Volker; Vogelsberger, Mark; Marinacci, Federico; Hernquist, Lars

    2016-01-01

    We present a constrained transport (CT) algorithm for solving the 3D ideal magnetohydrodynamic (MHD) equations on a moving mesh, which maintains the divergence-free condition on the magnetic field to machine-precision. Our CT scheme uses an unstructured representation of the magnetic vector potential, making the numerical method simple and computationally efficient. The scheme is implemented in the moving mesh code Arepo. We demonstrate the performance of the approach with simulations of driven MHD turbulence, a magnetized disc galaxy, and a cosmological volume with primordial magnetic field. We compare the outcomes of these experiments to those obtained with a previously implemented Powell divergence-cleaning scheme. While CT and the Powell technique yield similar results in idealized test problems, some differences are seen in situations more representative of astrophysical flows. In the turbulence simulations, the Powell cleaning scheme artificially grows the mean magnetic field, while CT maintains this co...

  5. Security of Linear Secret-Sharing Schemes Against Mass Surveillance

    DEFF Research Database (Denmark)

    Giacomelli, Irene; Olimid, Ruxandra; Ranellucci, Samuel

    2015-01-01

    Following the line of work presented recently by Bellare, Paterson and Rogaway, we formalize and investigate the resistance of linear secret-sharing schemes to mass surveillance. This primitive is widely used to design IT systems in the modern computer world, and often it is implemented by a prop...... there exists an undetectable subversion of it that efficiently allows surveillance. Second, we formalize the security notion that assures that a sharing scheme is secure against ASAs and construct the first sharing scheme that meets this notion....... by a proprietary code that the provider (“big brother”) could manipulate to covertly violate the privacy of the users (by implementing Algorithm-Substitution Attacks or ASAs). First, we formalize the security notion that expresses the goal of big brother and prove that for any linear secret-sharing scheme...

  6. Entanglement-assisted operator codeword stabilized quantum codes

    Science.gov (United States)

    Shin, Jeonghwan; Heo, Jun; Brun, Todd A.

    2016-05-01

    In this paper, we introduce a unified framework to construct entanglement-assisted quantum error-correcting codes (QECCs), including additive and nonadditive codes, based on the codeword stabilized (CWS) framework on subsystems. The CWS framework is a scheme to construct QECCs, including both additive and nonadditive codes, and gives a method to construct a QECC from a classical error-correcting code in standard form. Entangled pairs of qubits (ebits) can be used to improve capacity of quantum error correction. In addition, it gives a method to overcome the dual-containing constraint. Operator quantum error correction (OQEC) gives a general framework to construct QECCs. We construct OQEC codes with ebits based on the CWS framework. This new scheme, entanglement-assisted operator codeword stabilized (EAOCWS) quantum codes, is the most general framework we know of to construct both additive and nonadditive codes from classical error-correcting codes. We describe the formalism of our scheme, demonstrate the construction with examples, and give several EAOCWS codes

  7. Pretzel scheme for CEPC

    Science.gov (United States)

    Geng, Huiping

    2016-11-01

    CEPC was proposed as an electron and positron collider ring with a circumference of 50-100 km to study the Higgs boson. Since the proposal was made, the lattice design for CEPC has been carried out and a preliminary conceptual design report has been written at the end of 2014. In this paper, we will describe the principles of pretzel scheme design, which is one of most important issues in CEPC lattice design. Then, we will show the modification of the lattice based on the lattice design shown in the Pre-CDR. The latest pretzel orbit design result will also be shown. The issues remained to be solved in the present design will be discussed and a brief summary will be given at the end.

  8. Irregular and regular LDPC codes with high spectrum efficiency modulation in image transmission over fading channel

    Institute of Scientific and Technical Information of China (English)

    Ma Piming; Yuan Dongfeng

    2005-01-01

    If the degree distribution is chosen carefully, the irregular low-density parity-check (LDPC) codes can outperform the regular ones. An image transmission system is proposed by combining regular and irregular LDPC codes with 16QAM/64QAM modulation to improve both efficiency and reliability. Simulaton results show that LDPC codes are good coding schemes over fading channel in image communication with lower system complexity. More over, irregular codes can obtain a code gain of about 0.7 dB compared with regular ones when BER is 10-4. So the irregular LDPC codes are more suitable for image transmission than the regular codes.

  9. Coding of hyperspectral imagery using adaptive classification and trellis-coded quantization

    Science.gov (United States)

    Abousleman, Glen P.

    1997-08-01

    A system is presented for compression of hyperspectral imagery. Specifically, DPCM is used for spectral decorrelation, while an adaptive 2D discrete cosine transform coding scheme is used for spatial decorrelation. Trellis coded quantization is used to encode the transform coefficients. Side information and rate allocation strategies are discussed. Entropy-constrained codebooks are designed using a modified version of the generalized Lloyd algorithm. This entropy constrained system achieves a compression ratio of greater than 70:1 with an average PSNR of the coded hyperspectral sequence approaching 41 dB.

  10. Content Layer progressive Coding of Digital Maps

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Jensen, Ole Riis

    2002-01-01

    A new lossless context based method is presented for content progressive coding of limited bits/pixel images, such as maps, company logos, etc., common on the World Wide Web. Progressive encoding is achieved by encoding the image in content layers based on color level or other predefined informat......A new lossless context based method is presented for content progressive coding of limited bits/pixel images, such as maps, company logos, etc., common on the World Wide Web. Progressive encoding is achieved by encoding the image in content layers based on color level or other predefined...... information. Information from already coded layers are used when coding subsequent layers. This approach is combined with efficient template based context bilevel coding, context collapsing methods for multilevel images and arithmetic coding. Relative pixel patterns are used to collapse contexts. Expressions...... for calculating the resulting number of contexts are given. The new methods outperform existing schemes coding digital maps and in addition provide progressive coding. Compared to the state-of-the-art PWC coder, the compressed size is reduced to 50-70% on our layered map test images....

  11. Efficient On-line Schemes for Encoding Individual Sequences with Side Information at the Decoder

    CERN Document Server

    Reani, Avraham

    2009-01-01

    We present adaptive on-line schemes for lossy encoding of individual sequences under the conditions of the Wyner-Ziv (WZ) problem. In the first part of this article, a set of fixed-rate scalar source codes with zero delay is presented. We propose a randomized on-line coding scheme, which achieves asymptotically (and with high probability), the performance of the best source code in the set, uniformly over all source sequences. The scheme uses the same rate and has zero delay. We then present an efficient algorithm for implementing our on-line coding scheme in the case of a relatively small set of encoders. We also present an efficient algorithm for the case of a larger set of encoders with a structure, using the method of the weighted graph and the Weight Pushing Algorithm (WPA). In the second part of this article, we extend our results to the case of variable-rate coding. A set of variable-rate scalar source codes is presented. We generalize the randomized on-line coding scheme, to our case. This time, the p...

  12. Algebraic Approach to Physical-Layer Network Coding

    CERN Document Server

    Feng, Chen; Kschischang, Frank R

    2011-01-01

    The problem of designing physical-layer network coding (PNC) schemes via lattice partitions is considered. Building on the compute-and-forward (C&F) relaying strategy of Nazer and Gastpar, who demonstrated its asymptotic gain using information-theoretic tools, an algebraic approach is taken to show its potential in practical, non-asymptotic, settings. A general framework is developed for studying lattice-partition-based PNC schemes---called lattice network coding (LNC) schemes for short---by making a direct connection between C&F and module theory. In particular, a generic LNC scheme is presented that makes no assumptions on the underlying lattice partition. C&F is re-interpreted in this framework, and several generalized constructions of LNC schemes are given based on the generic LNC scheme. Next, the error performance of LNC schemes is analyzed, with a particular focus on hypercube-shaped LNC schemes. The error probability of this class of LNC schemes is related to certain geometric parameters o...

  13. Code-excited linear predictive coding of multispectral MR images

    Science.gov (United States)

    Hu, Jian-Hong; Wang, Yao; Cahill, Patrick

    1996-02-01

    This paper reports a multispectral code excited linear predictive coding method for the compression of well-registered multispectral MR images. Different linear prediction models and the adaptation schemes have been compared. The method which uses forward adaptive autoregressive (AR) model has proven to achieve a good compromise between performance, complexity and robustness. This approach is referred to as the MFCELP method. Given a set of multispectral images, the linear predictive coefficients are updated over non-overlapping square macroblocks. Each macro-block is further divided into several micro-blocks and, the best excitation signals for each microblock are determined through an analysis-by-synthesis procedure. To satisfy the high quality requirement for medical images, the error between the original images and the synthesized ones are further specified using a vector quantizer. The MFCELP method has been applied to 26 sets of clinical MR neuro images (20 slices/set, 3 spectral bands/slice, 256 by 256 pixels/image, 12 bits/pixel). It provides a significant improvement over the discrete cosine transform (DCT) based JPEG method, a wavelet transform based embedded zero-tree wavelet (EZW) coding method, as well as the MSARMA method we developed before.

  14. Locally Orderless Registration Code

    DEFF Research Database (Denmark)

    2012-01-01

    This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows.......This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows....

  15. Locally orderless registration code

    DEFF Research Database (Denmark)

    2012-01-01

    This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows.......This is code for the TPAMI paper "Locally Orderless Registration". The code requires intel threadding building blocks installed and is provided for 64 bit on mac, linux and windows....

  16. Design and evaluation of sparse quantization index modulation watermarking schemes

    Science.gov (United States)

    Cornelis, Bruno; Barbarien, Joeri; Dooms, Ann; Munteanu, Adrian; Cornelis, Jan; Schelkens, Peter

    2008-08-01

    In the past decade the use of digital data has increased significantly. The advantages of digital data are, amongst others, easy editing, fast, cheap and cross-platform distribution and compact storage. The most crucial disadvantages are the unauthorized copying and copyright issues, by which authors and license holders can suffer considerable financial losses. Many inexpensive methods are readily available for editing digital data and, unlike analog information, the reproduction in the digital case is simple and robust. Hence, there is great interest in developing technology that helps to protect the integrity of a digital work and the copyrights of its owners. Watermarking, which is the embedding of a signal (known as the watermark) into the original digital data, is one method that has been proposed for the protection of digital media elements such as audio, video and images. In this article, we examine watermarking schemes for still images, based on selective quantization of the coefficients of a wavelet transformed image, i.e. sparse quantization-index modulation (QIM) watermarking. Different grouping schemes for the wavelet coefficients are evaluated and experimentally verified for robustness against several attacks. Wavelet tree-based grouping schemes yield a slightly improved performance over block-based grouping schemes. Additionally, the impact of the deployment of error correction codes on the most promising configurations is examined. The utilization of BCH-codes (Bose, Ray-Chaudhuri, Hocquenghem) results in an improved robustness as long as the capacity of the error codes is not exceeded (cliff-effect).

  17. A Two-dimensional Magnetohydrodynamics Scheme for General Unstructured Grids

    Science.gov (United States)

    Livne, Eli; Dessart, Luc; Burrows, Adam; Meakin, Casey A.

    2007-05-01

    We report a new finite-difference scheme for two-dimensional magnetohydrodynamics (MHD) simulations, with and without rotation, in unstructured grids with quadrilateral cells. The new scheme is implemented within the code VULCAN/2D, which already includes radiation hydrodynamics in various approximations and can be used with arbitrarily moving meshes (ALEs). The MHD scheme, which consists of cell-centered magnetic field variables, preserves the nodal finite difference representation of divB by construction, and therefore any initially divergence-free field remains divergence-free through the simulation. In this paper, we describe the new scheme in detail and present comparisons of VULCAN/2D results with those of the code ZEUS/2D for several one-dimensional and two-dimensional test problems. The code now enables two-dimensional simulations of the collapse and explosion of the rotating, magnetic cores of massive stars. Moreover, it can be used to simulate the very wide variety of astrophysical problems for which multidimensional radiation magnetohydrodynamics (RMHD) is relevant.

  18. Improved Ternary Subdivision Interpolation Scheme

    Institute of Scientific and Technical Information of China (English)

    WANG Huawei; QIN Kaihuai

    2005-01-01

    An improved ternary subdivision interpolation scheme was developed for computer graphics applications that can manipulate open control polygons unlike the previous ternary scheme, with the resulting curve proved to be still C2-continuous. Parameterizations of the limit curve near the two endpoints are given with expressions for the boundary derivatives. The split joint problem is handled with the interpolating ternary subdivision scheme. The improved scheme can be used for modeling interpolation curves in computer aided geometric design systems, and provides a method for joining two limit curves of interpolating ternary subdivisions.

  19. Formal Verification of NTRUEncrypt Scheme

    Directory of Open Access Journals (Sweden)

    Gholam Reza Moghissi

    2016-04-01

    Full Text Available In this paper we explore a mechanized verification of the NTRUEncrypt scheme, with the formal proof system Isabelle/HOL. More precisely, the functional correctness of this algorithm, in its reduced form, is formally verified with computer support. We show that this scheme is correct what is a necessary condition for the usefulness of any cryptographic encryption scheme. Besides, we present a convenient and application specific formalization of the NTRUEncrypt scheme in the Isabelle/HOL system that can be used in further study around the functional and security analysis of NTRUEncrypt family.

  20. The Research of Unconditionally Secure Authentication Code For Multi-Source Network Coding

    Directory of Open Access Journals (Sweden)

    Hong Yang

    2011-03-01

    Full Text Available in a network system, network coding allows intermediate nodes to encode the received messages before forwarding them, thus network coding is vulnerable to pollution attacks. Besides, the attacks are amplified by the network coding process with the result that the whole network maybe polluted. In this paper, we proposed a novel unconditionally secure authentication code for multi-source network coding, which is robust against pollution attacks. For the authentication scheme based on theoretic strength, it is robust against those attackers that have unlimited computational resources, and the intermediate nodes therein can verify the integrity and origin of the encoded messages received without having to decode them, and the receiver nodes can check them out and discard the messages that fail the verification. By this way, the pollution is canceled out before reaching the destinations.